PT3E-04919

Explosion-Proof Calorimeter

OHC-800
Operating Manual

2-7-6 Azusawa, Itabashi-ku, Tokyo, 174-8744, Japan
Phone ： +81-3-3966-1113
Fax： +81-3-3558-9110
E-mail ： intdept@rikenkeiki.co.jp
Web site ： https://www.rikenkeiki.co.jp/english/

1 Important Notices on Safety

1-1. Danger cases

Thank you for choosing our explosion-proof calorimeter OHC-800.
This manual explains how to use the calorimeter and its specifications. It contains information required forusing the calorimeter properly. Not only the first-time users but also the users who have already used the
product must read and understand the operating manual to enhance the knowledge and experience before
using the calorimeter.
Throughout this manual, the following indications are used to ensure safe and effective work.
DANGER

This message indicates that improper handling may cause death or serious
damage on health or assets.

WARNING

This message indicates that improper handling may cause serious damage on
health or assets.

CAUTION

This message indicates that improper handling may cause minor damage on
health or assets.

NOTE

This message indicates advice on handling.

Note) MODBUS is registered trademarks of Schneider automation inc.

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1 Important Notices on Safety

1-1. Danger cases<Contents>
1. Important Notices on Safety ...................................................................................................................................... 5
1-1. Danger cases ................................................................................................................................................... 5
1-2. Warning cases .................................................................................................................................................. 6
1-3. Precautions ...................................................................................................................................................... 7
1-4. Method of confirmation for Standards and Explosion proof specification ......................................................... 7
1-5. Information about explosion-proof performance (Japan Ex spec.) ................................................................... 8
1-5-1. About OHC-800 ....................................................................................................................................... 8
1-5-2. Technical data .......................................................................................................................................... 8
1-5-3. System configuration for use in hazardous location ................................................................................ 9
1-6. Information about explosion-proof performance (ATEX/IECEx spec.) .............................................................. 10
1-6-1. About OHC-800 ....................................................................................................................................... 10
1-6-2. Technical data .......................................................................................................................................... 10
1-6-3. System configuration for use in hazardous location ................................................................................ 11
1-6-4. Notice on safety ....................................................................................................................................... 12
2. Product Components................................................................................................................................................. 15
2-1. Purpose of use and features of this product ..................................................................................................... 15
2-2. Main unit and standard accessories ................................................................................................................. 16
2-3. Names of internal product components ............................................................................................................ 17
2-4. Names and functions of display........................................................................................................................ 18
3. How to Install Calorimeter ......................................................................................................................................... 19
3-1. Precautions on installation site ......................................................................................................................... 19
3-2. Installation procedure and required maintenance space .................................................................................. 20
3-3. How to connect wire ......................................................................................................................................... 21
3-3-1. Description of terminal block.................................................................................................................... 21
3-3-2. Recommended cables ............................................................................................................................. 23
3-3-3. How to lead in and connect cables .......................................................................................................... 24
3-3-4. Protective grounding ................................................................................................................................ 26
3-3-5. Precautions on electrical work ................................................................................................................. 27
3-4. How to tube ...................................................................................................................................................... 30
3-4-1. Sampling device ...................................................................................................................................... 30
3-4-2. Recommended external tubing system ................................................................................................... 31
3-4-3. Precautions on tubing work ..................................................................................................................... 32
4. How to Operate in MEASURING MODE ................................................................................................................... 33
4-1. From display just after power-on to measurement start.................................................................................... 33
4-2. How to switch display screens.......................................................................................................................... 35
4-3. Switching to other mode ................................................................................................................................... 36
4-4. Self-diagnostic function .................................................................................................................................... 37
4-5. Operations of contacts, display, and signal output after recovery to normal state ............................................ 38
5. How to Operate in Check Mode ................................................................................................................................ 39
5-1. Menu items of CHECK MODE.......................................................................................................................... 40
5-2. Items and details .............................................................................................................................................. 41
5-2-1. Check of optical sensor unit state (OPTICAL SENSOR UNIT CONDITION) ........................................... 41
5-2-2. Check of sonic sensor unit state (SONIC SENSOR UNIT CONDITION) ................................................. 42
5-2-3. Check of main controller state (MAIN CONTROLLER CONDITION)....................................................... 42
5-2-4. Check of measuring conditions for calorific value (CALORIFIC VALUE PARAMETER) .......................... 43
5-2-5. Check of measuring conditions for density (DENSITY PARAMETER) .................................................... 43
5-2-6. Check of 4 - 20 mA settings (4 - 20 mA PARAMETER) ........................................................................... 43
5-2-7. Check of pressure sensor output (PRESSURE SENSOR READINGS) .................................................. 44
5-2-8. Check of temperature sensor output (TEMPERATURE SENSOR READINGS) ...................................... 44
5-2-9. Check of calorific value calculation settings (CALCULATION FACTOR (CALORIFIC VALUE)) .............. 45
5-2-10. Check of density calculation settings (CALCULATION FACTOR (DENSITY))....................................... 45
5-2-11. Check of Opt-Sonic calculation process (OPT-SONIC READINGS) ...................................................... 46
5-2-12. Check of display and contact settings (DISP. & CONTACT PARAMETER) ........................................... 46
5-2-13. Latching reset for display and contact (LATCHING RESET (DISP. & CONTACT)) ................................ 47
6. How to Operate in SETUP MODE ............................................................................................................................. 48
6-1. SETUP MODE items ........................................................................................................................................ 50
6-2. Items and details .............................................................................................................................................. 51
6-2-1. Setting of calorific value calculation conditions (CALCULATION FACTOR (CALORIFIC VALUE)) ......... 51
6-2-2. Setting of density calculation conditions (CALCULATION FACTOR (DENSITY)) .................................... 52

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1 Important Notices on Safety

1-1. Danger cases

6-2-3. 4 – 20 mA condition settings (4 – 20 mA SETTINGS).............................................................................. 53
6-2-4. 4 – 20 mA output adjustment (4 – 20 mA ADJUSTMENT) ....................................................................... 54
6-2-5. 4 – 20 mA output test (4 – 20 mA TEST) ................................................................................................. 55
6-2-6. Reference calibration (REF. CALIBRATION) ........................................................................................... 56
6-2-7. Offset (OFFSET ADJUSTMENT) ............................................................................................................. 57
6-2-8. Display and contact operation settings (DISP. & CONTACT SETTINGS) ................................................ 58
6-2-9. LCD display settings (LCD DISPLAY SETTINGS) ................................................................................... 59
6-2-10. RS-485 (MODBUS) communication settings (RS-485(MODBUS) SETTINGS)..................................... 60
6-2-11. Change of energized contact settings (CONTACT SETTINGS) ............................................................. 61
6-2-12. Check the contact operation (CONTACT TEST) .................................................................................... 61
6-2-13. Password change (PASSWORD SETUP (SETUP MODE)) .................................................................. 62
6-2-14. Log data download (IrDA COMMUNICATION) ...................................................................................... 62
7. Maintenance63
7-1. Maintenance intervals and items ...................................................................................................................... 63
7-1-1. Daily maintenance ................................................................................................................................... 63
7-1-2. Monthly regular maintenance .................................................................................................................. 64
7-1-3. Biannual regular maintenance ................................................................................................................. 65
7-2. Recommended regular replacement parts ....................................................................................................... 66
8. Storage, Relocation, and Disposal ............................................................................................................................ 67
8-1. Procedures to store the calorimeter or leave it for a long time ......................................................................... 67
8-2. Procedures to relocate the calorimeter or use it again ..................................................................................... 67
8-3. Disposal of products ......................................................................................................................................... 68
9. Troubleshooting ......................................................................................................................................................... 69
9-1. <FAILURE> ...................................................................................................................................................... 69
9-2. <OUT OF SPECIFICATION>............................................................................................................................ 72
9-3. <MAINTENANCE REQUIRED> ....................................................................................................................... 74
9-4. <FUNCTION CHECK> ..................................................................................................................................... 75
9-5. CAUTION screen ............................................................................................................................................. 76
9-6. Others............................................................................................................................................................... 77
9-7. If not applicable to display ................................................................................................................................ 78
10. Product Specifications ............................................................................................................................................. 79
10-1. Product specifications..................................................................................................................................... 79
10-2. Principle of this product .................................................................................................................................. 80
10-2-1. Opt-Sonic calculation (calorific value) .................................................................................................... 80
10-2-2. Opt-Sonic calculation (specific gravity) .................................................................................................. 82
10-2-3. Principle of optical sensor ...................................................................................................................... 84
10-2-4. Principle of sonic sensor ........................................................................................................................ 85
11. Definition of Terms ................................................................................................................................................... 86
11-1. Definition of terms used in operating manual .................................................................................................. 86
11-2. Definition of terms used in "Measuring gas specification sheet" ..................................................................... 87

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1 Important Notices on Safety

1-1. Danger cases

1

Important Notices on
Safety1-1. Danger cases
DANGER<About explosion-proof> Satisfy the following installtaion requirements of the calorimeter.
 Do not open the lid during operation.
 Turn off the power of the calorimeter before replacing the fuse.
(Fuse specifications: 250 V, 1 A, Φ5 x 20 mm, time lag type) Do not disassemble/modify the calorimeter, or change the settings if not necessary.
Contact RIKEN KEIKI for information on readjustment including gas calibration and parts
replacement.
 Do not replace parts at your sole discretion but contact RIKEN KEIKI if the transparent window has acrack or the explosion-proof joint surface is abnormal, or the clamping screw or bolt is changed, lostetc.
 Never fail to perform a regular maintenance.
 Use appropriate cables to wire.
 Use ring terminals etc. for electrical connections and ensure safe connection without any slack ortangle.
 Use ring terminals to connect the grounding terminal with the ground and use the grounding wirewith cross-sectional area of 4 mm2 or more for the external grounding terminal.
 The transparent window is made of polycarbonate resin. Be careful that it may be damaged by anatmosphere of toluene, benzene, ammonia, aromatic hydrocarbon etc.
 Do not repair the explosion-proof joint surface.
 Use a control key (magnet) specified by RIKEN KEIKI.
 Gas conditions (Explosion protection conditions)
Maximum flow rate Measuring gas (GAS IN) 1 L/min
Reference gas (REF IN) 0.5 L/min
Pressure
80 to 110 kPa for all of GAS IN, REF IN, and OUT
Temperature-20 to 57°C for all of GAS IN, REF IN, and OUT(Japan Ex spec.)-20 to 60°C for all of GAS IN, REF IN, and OUT(ATEX/IECEx/China Ex spec.)

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1 Important Notices on Safety

1-2. Warning cases

1-2. Warning cases
WARNING<About explosion-proof>
Do not open the front lid of the OHC-800 if the existence of an explosive atmosphere is suspected.

WARNING<Power>
Before turning on the calorimeter, always check that the voltage is properly applied. Do not use an
unstable power supply because it may cause malfunctions.
The settings in the calorimeter vary depending on the AC and DC power specifications (See thefigure below).
The calorimeter is damaged if incorrect power is supplied to incorrect settings.
Check the specifications and supply the correct power.

Power terminal unit withAC specifications

Power terminal unit withDC specifications

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1 Important Notices on Safety

1-3. Precautions

1-3. Precautions
CAUTION
Do not use a transceiver near the calorimeter.
Radio wave from a transceiver near the calorimeter or its cables may disturb indication reading. If atransceiver is used, it must be used in a place where it disturbs nothing.
To restart the calorimeter, wait for five seconds or more before doing it.
Restarting the calorimeter within five seconds may cause errors.
Do not disassemble/modify the calorimeter, or change the settings if not necessary.
Disassembling/modifying the calorimeter will invalidate the warranty of the performance. Changing
the settings without understanding the specifications may cause malfunctions. Please use thecalorimeter properly in accordance with the operating manual.
Avoid applying organic solvents and others to the window plate for a long time.
The window plate material is a polycarbonate resin. When organic solvents (liquid or
highly-concentrated vapor) and others are applied to the plate for a long time, its color and shape
may be changed.

1-4. Method of confirmation for Standards andExplosion proof specification
This instrument has some specification depends on standard and explosion proof certificate. Pleaseconfirm the detector specification before using. Please refer Declaration of Conformity that is at the end of
this manual if you have CE marking type (DC specifications only).
You can confirm instrument specification to see name plate as follows.
Ex marking
CE marking

ATEX/IECEx, CE marking
spec name plate

Japan Excertificate

China Ex spec name plate

Japan Ex spec name plate*Attached to the front of the product.

*Attached to the front of the product.

*Attached to the front of the product.

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1 Important Notices on Safety

1-5. Information about explosion-proof performance (Japan Ex spec.)

1-5. Information about explosion-proof performance(Japan Ex spec.)

1-5-1. About OHC-800
The OHC-800 is an explosion-proof calorimeter. According to measured calorific values, 4 - 20 mA signals
and digital signals are output.
The calorimeter is used for the purposes of calorific value recording and device control by conntecting it to arecorder or a programmable controller.
The calorimeter has three contact outputs and these are activated by malfunction etc. of the device.

1-5-2. Technical data
Explosion-proof structure
Certificate number (Japan Ex)
Explosion-proof class

Flame-proof enclosures
No. TC20344

Ambient temperature
RatingPower supply-20 to 57°C
100 VAC/110 mA - 240 VAC/70 mA, 50/60 Hz,
24 VDC/190 mA
24 VDC/0 - 22 mA

Analog signal
outputDigital signal
input-output
Contact output(Contact capacity)
Applied standard

Ex d ⅡB+H2 T4

RS-485 (MODBUS)
240 VAC/20 W (Load resistance)
30 VDC/2 A (Load resistance)
30 VDC/2 A (Load resistance)JNIOSH－TR－NO.43 (2008)

Manufacturer: RIKEN KEIKI CO., LTD.
2-7-6 Azusawa, Itabashi-ku, Tokyo, 174-8744 JapanWeb site: https://www.rikenkeiki.co.jp/

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1 Important Notices on Safety

1-5. Information about explosion-proof performance (Japan Ex spec.)

1-5-3. System configuration for use in hazardous location
The OHC-800 has a flame-proof enclosure (Explosion-proof class: Ex dⅡB+H2 T4) and can be used in a
Class 1 location. However, if the power source and display instrument etc. connected to it do not have an
explosion-proof structure, install it in a non-hazardous area.

Hazardous area

Non-hazardous area

Calorimeter (OHC-800)
AC/DC power source
Display instrument

Display instrument

Display instrument

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1 Important Notices on Safety

1-6. Information about explosion-proof performance (ATEX/IECE spec.)

1-6. Information about explosion-proof performance(ATEX/IECE spec.)

1-6-1. About OHC-800
This product is a sample draw type fixed Calorimeter.
2 power inputs, AC and DC, are available on the Calorimeter.

1-6-2. Technical data
(Name) :CALORIMETER(Type) :OHC-800(Protection Method) : Flameproof enclosure “d”(Certificate numbers)IECEx DEK 12.0058X
DEKRA 12ATEX0187 X(Group) : II
(Category) : 2 G(Type of Protection and Marking code) : Ex db IIB+H2 T4(Equipment Protection Level) : Gb
(Ambient Temperature) : -20℃ ~ 60℃(Electrical Data):
Supply voltage : 100VAC/95mA～240VAC/70mA 50 /60 Hz
or 24 VDC/190mA
Contact output : 30VDC/2A
Contact output : 240VAC/1A
Output signal : 4-20mA (24 VDC/20mA)
Digital Communication :RS485(Applicable Standard) EN IEC 60079-0:2018, EN 60079-1:2014
IEC 60079-0:2017, IEC 60079-1:2014-6

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1 Important Notices on Safety

1-6. Information about explosion-proof performance (ATEX/IECE spec.)

1-6-3. System configuration for use in hazardous location

Installation Diagram
Hazardous Location

Nonhazardous Location

CaloriMeter (OHC‐800)
L/+
N/‐
PE

AC Power / DC Power
Indicator etc.

Sig+
Sig‐

CVVS Cable

Sig+
Sig‐

Indicator etc.
RLY

RLY

RLY

RLY

RLY

CVVS Cable

RLY

Indicator etc.

RS485

RS485
CVVS Cable

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1 Important Notices on Safety

1-6. Information about explosion-proof performance (ATEX/IECE spec.)

1-6-4. Notice on safety
WARNING・Do not open when an explosive atmosphere is present.
Caution・Do not open the cover while in operation.
・Do not take apart, remodel and change the instrument.
・Contact the nearest Riken Keiki’s agents or Riken Keiki to perform adjustment, including the gas
calibration, and parts replacement etc.
・Contact the nearest Riken Keiki’s agents or Riken Keiki if any abnormalities are found.
・Make sure to perform a regular check.
・Make sure to use suitable cables.
・Do not repair the flame-proof composition surface.
・All bolt with the hexagon socket must use the stainless steel material of property
class "A2-70".
・The internal and external ground connection shall be made with a cable lug and be
secured by additional means to prevent twisting.
・At the internal ground connection the cable lug shall be installed between
the washer and the toothed lock washer.
・Gas conditions
Composition
IIC gases other than H2 cannot be used.
Max Flow
Measurement gas:1L/min
Reference Gas:0.5L/min
Pressure range
Measurement Gas Reference Gas Out Gas : 80～110kPa
Temperature
Measurement Gas Reference Gas Out Gas :-20～60℃

・In case oxygen presents in the sampling gas which is supplied into OHC-800 and emitted
from OHC-800, contents of oxygen should be lower than that normally present in air.
・The sampling gas which is supplied into OHC-800 and emitted from OHC-800 should not be within
the explosive limits continuously for long period or frequency.
・Power on the measuring system after pipings in the enclosure are purged with process gas.
Also, power off the measuring system while pipings in the enclosure are purged with process gas.
・Periodic maintenance service shall be performed to check if there is no failure of the gas containment.

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1 Important Notices on Safety

1-6. Information about explosion-proof performance (ATEX/IECE spec.)

Earth terminal

Cable gland

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1 Important Notices on Safety

1-6. Information about explosion-proof performance (ATEX/IECE spec.)

Please install a cable gland into OHC-800 according to the following figure.

Please tighten a bolt of a cable gland at 40N･m or more

Special conditions for safe use
・Repair of the flameproof joints is not allowed.
・Fasteners have property class A2-70.

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2 Product Components

2-1. Purpose of use and features of this product2

Product Components
2-1. Purpose of use and features of this product This calorimeter is an explosion-proof calorimeter in a flame-proof enclosure designed for continuous,fast-response measurement of the "Calorific value," "Density," and "WOBBE index" of various fuel gases
such as natural gas, coke oven gas, blast furnace gas, converter gas, biomass gas, and biogas.
The types of fuel gases that can be measured depend on the specifications. For information on the typesof gases that can be measured by the product, check the "Measuring gas specification sheet" provided
with it.
 The calorimeter measures the speeds of "light" and "sound" that travel through the measuring gas byusing an "optical sensor" and a "sonic sensor" and applying the Opt-Sonic calculation processing* to themeasuring result. This enables the high-accuracy measurement of "Calorific value" and "Density" of fuelgases containing interference gases such as nitrogen and carbon dioxide.

NOTE
For information on Opt-Sonic calculation, see Section 10.2, "Principle of this product."
Opt-Sonic calculation is a coined word by RIKEN KEIKI.
 The calorimeter can be used with minimum equipment even under constraint conditions with its highevironmental resistance.
 The calorimeter, having an advanced self-monitoring/diagnostic function compliant with NAMUR NE107(self-monitoring/diagnostic of field devices), offers functions for performing real-time status monitoringfor devices and informing abnormal statuses and maintenance requests with LCD display and contact
output.
 The calorimeter has a log data auto-save function that records the history of "operation statuses" and"self-diagnostic results" for a year or longer. Furthermore, another function provides outputting the log
data via IrDA communication, which can be used for high-quality maintenance/follow-up services.
(Optional services) The calorimeter forms a "complete stand-alone unit structure" that consists of standardized units. Even if
any malfunction occurs, quick repair and recovery can be achieved just by replacing a faulty unit on site.

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2 Product Components

2-2. Main unit and standard accessories

2-2. Main unit and standard accessories<Main unit> (including cable glands)

Cable gland<Standard accessories>






Operating manual
Measuring gas specification sheet
Dedicated control key (magnet)
Hex key wrench (2 mm and 6 mm, one each)
Fuse (250V 1A Φ5 x 20 mm，two)

CAUTION Use the supplied dedicated magnet control key to operate the calorimeter. If products other thanthese accessories are used, key operations cannot be accepted properly.
 The magnet control key is made of an extremely strong magnet. Keep it away from a credit card,
ID card, or other magnetic product because stored data may be destroyed.

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2 Product Components

2-3. Names of internal product components

2-3. Names of internal product components
Optical sensor unit

Sonic sensor unit

Main controller

Name
Optical sensor unit

Sonic sensor unit
Power terminal unit

Main controller

Power terminal unit

Functions
Measures the speed of light that travels through the measuring gas bycapturing the refractive index. In addition, this unit monitors the flow rates ofthe measuring gas and REF gas.
Measures the speed of sound that travels through the measuring gas.
Supplies power to other units.
This unit relays signals between units, performs contact output, and outputs
4 - 20 mA analog signals and RS-485 (MODBUS) communication signals.
Calculates and displays the "Calorific value," "Density," and "WOBBE index"
based on data received from the optical sensor unit and the sonic sensor
unit. Also converts the units of "Calorific value" and "Density."
Checks the operation statuses of other units to ensure normal measurement
and output.

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2 Product Components

2-4. Names and functions of display

2-4. Names and functions of display

Ⅱ2G Ex dbⅡB+H2 T4 Gb

 MODE/ESC key
 POWER lamp (green) EV1 lamp (orange) EV2 lamp (red) EV3 lamp (green)
 ▲ key DISP/SET key
 LCD display
 IrDA communication port ▼ key

Switches MEASURING MODE to other mode.
Used to stop processing.
Lights up at power-on.
Lights up in conjunction with Contact Output 1.
Lights up in conjunction with Contact Output 2.
Lights up in conjunction with Contact Output 3.
Moves the cursor or increases the setting value.
Switches the display content in MEASURING MODE.
Confirms processing etc.
Displays measurement values, operation statuses, or otherinformation.
The IrDA communication port for maintenance. Reads event log ordaily log information recorded on the product.
Moves the cursor or decreases the setting value.

Use the attached magnet control key to operate all the switches
described in the above table. Holding the magnet control key
over the switch marks for a few seconds will start the switches.
The description of "press the XXX switch" in this operating manualmeans holding the magnet control key over the marks  and ▼▲.

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Control key (magnet)

3 How to Install Calorimeter3-1. Precautions on installation site

3

How to Install Calorimeter3-1. Precautions on installation site
Use the calorimeter in combination with a sampling device specified by RIKEN KEIKI (or an equivalent
cubicle). Do not install this product in any of the following locations.

(1) Place where the calorimeter is exposed to oil,chemicals etc.

(2) Place with vibrations(3) Place where radio wave or noise is generated(4) Place where the calorimeter may drop or
receive strong shock(5) Place exceeding the operating temperature
range
Place where the calorimeter is exposed to direct
sunlight or radiant heat

(6) Place where maintenance of the calorimetercannot be performed
Place where handling of the calorimeter involves
dangers

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3 How to Install Calorimeter3-2. Installation procedure and required maintenance space

3-2. Installation procedure and required maintenancespace
Install the OHC-800 and thesampling device on the surface of arobust wall or a freestanding racketc. using bolts.
Before installation, a maintenancespace shown in the figure on theright must be secured.
Be sure to secure this space during
construction planning or installation.

Maintenance space

CAUTION(Unit: mm)

 Do not drop or give strong shock to the calorimeter during transportation or installation.
Otherwise, the calorimeter may be damaged, or the explosion-proof performance may be lost.
 When installing the calorimeter on a freestanding rack (fixed type), fix the freestanding rack withanchor bolts.
 If the calorimeter is to be fixed on the wall, install it properly where it can hold its weight.
 When performing construction work, prevent dust from entering the inside of the calorimeter.

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3 How to Install Calorimeter3-3. How to connect wire

3-3. How to connect wire
3-3-1. Description of terminal block
Open the front lid of the OHC-800 to find the terminal blockshown in the figure below. The terminal block has thelayout shown in the table below.

(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)

Contact output
1

CONTACT
1

Activates if the FUNCTION CHECK condition is met or the OUT OF
SPECIFICATION condition is met.
[No-voltage contact, contact capacity of 2 A, 30 VDC (resistance load)]

Contact output
2

CONTACT
2

Activates if the FAILURE condition is met.
[No-voltage contact, contact capacity of 2 A, 30 VDC (resistance load)]

Contact output
3

CONTACT
3

Activates if the MAINTENANCE REQUIRED condition is met.
[SSR contact, contact capacity of 20 W, 240 VAC (resistance load)]

Power

FG
L/+
N/-

RS-485
communication

A
B
G
Y
Z

Functional Grounding (EARTH)
100 - 240 VAC ±10%, 50/60 Hz, max. 18 VA
or 24 VDC ± 10%, max. 5 W

Input-output terminals for communication via RS-485 (MODBUS)

4 - 20 mA DC (isolated, source current type) maximum load resistanceof 300 Ω(16)(-)
Minimum resolution of 0.01 mA or lessM4 is used as the terminal screws for the terminal block. Attach an insulated ring terminal for M4 to the tipof a cable for wiring.
(15)

4 - 20 mA
external output

(+)

NOTE
・If you are considering the use of the RS-485 (MODBUS) communication function, contact RIKEN KEIKI.
・The "b" contact (break contact) under de-energized state may be opened momentarily by a physicalshock, such as external force.
When the "b" contact is selected for the alarm contact, take appropriate actions to prepare for a
momentary activation, for example, add signal delay operation (approximately one second) to thereceiving side of the "b" contact.

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3 How to Install Calorimeter3-3. How to connect wire

CAUTION
Contact output 3 (SSR)
 Contact output 3 is SSR output.
 AC power is required to activate Contact output 3
Method of changing the output from SSR to dry contact
 Add an external relay outside of OHC-800.
Contact output 3 is SSR output. (Load specification: 75 VAC - 264 VAC, Electronic current 20mA - 1A)
For this reason, the power terminal unit with DC specifications can not be used as it is when SSR
output is taken into.
In this case, add an external AC relay outside of OHC-800 and change the output from SSR to dry
contact.
< Wiring diagram >OHC-800(5)(6)
Hazardous area
Non hazardous area

Relay
～

100VAC～
Input unit

 Install the AC relay into non hazardous area
 Use a relay that coil specification is voltage 75 VAC - 264 VAC, electronic current 20mA - 1A.
Example) MK3ZP (OMRON): Rating current 23.1mA (100VAC, 60Hz)

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3 How to Install Calorimeter3-3. How to connect wire

3-3-2. Recommended cables
Connected to

Recommended cable2

Power (AC) line
Power (DC) line
4 - 20 mA line
Contact x 1 line
Contact x 2 lines
Contact x 3 lines
RS-485 line

Cable overall outer diameter

CVV 1.25 mm /3-core
CVV 2 mm2/3-core
CVVS 1.25 mm2/2-core
CVVS 2 mm2/2-core
CVVS 1.25 mm2/2-core
CVVS 2 mm2/2-core
CVVS 1.25 mm2/2-core
CVVS 2 mm2/2-core
CVVS 1.25 mm2/4-core
CVVS 2 mm2/4-core
CVVS 1.25 mm2/6-core
CVVS 2 mm2/6-core

Φ10.0
Φ11.0
Φ10.0
Φ11.0
Φ10.0
Φ11.0
Φ10.0
Φ11.0
Φ11.0
Φ12.0
Φ13.0
Φ14.0

KPEVS 0.75 mm2/2P

Φ11.0

CVV = Control -use Vinyl insulated Vinyl sheathed cable
CVVS = Control -use Vinyl insulated Vinyl sheathed cable with shield

NOTE
The overall outer diameters must be checked because they may somewhat vary between manufacturers.

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3 How to Install Calorimeter3-3. How to connect wire

3-3-3. How to lead in and connect cables
As shown on the right side of the figure below, attach the parts in the following order: (1) cable gland, (2)clamp washer, (3) washer, (4) rubber seal, and (5) washer to the cable, then connect the cable into lead-in
port through the enclosure by attaching an insulated ring terminal to the tip in order to complete theconnection to the terminal block.
An unused cable lead-in port must be closed with a rubber seal and a seal plug as shown on the left of the
figure below.

Set screw for fastening
Cable lead-in ports (five)(5) Washer
Rubber seal
(4) Rubber seal
(3) Washer(2) Clamp washer(Note: Place the rightside of the face)
Seal plug(1) Cable gland
Bad example

CAUTION

 Ensure the tightening torque for the cable gland and seal plug to be 40 Nꞏm or larger.
 If it is difficult to tighten the cable gland and seal plug, grease its screw part and then tighten
them with the tool.
 After completing tightening of the cable gland and seal plug, use a set screw for fastening toprevent it from loosening.
 To improve noise immunity, connect the shield of the CVVS cable inside the enclosure.

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3 How to Install Calorimeter3-3. How to connect wire

The rubber seals, washers, and clamp washers needed for cable connection vary depending on the overall
outer diameter of a cable to be used. The table below shows the relationships between the overall outer
diameters of cables and inner diameters of parts. Please specify parts needed for cables to be used.
Cable overall outer
diameter(mm)

Rubber seal
inner diameter (mm)Washerinner diameter (mm)Clamp washer
inner diameter (mm)Φ10, Φ10.5

Φ11

Φ12

Φ10.8

Φ11, Φ11.5

Φ12

Φ14

Φ11.8

Φ12, Φ12.5

Φ13

Φ14

Φ12.8

Φ13, Φ13.5

Φ14

Φ14

Φ13.8

Inner diameter
Inner diameter

Inner diameter

WasherClamp washer

Rubber seal
inner diameter

Rubber seal

(Unit: mm)

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3 How to Install Calorimeter3-3. How to connect wire

3-3-4. Protective grounding
Connect the calorimeter to the ground using the "external grounding terminal" or "No.(7) of the terminal
block" shown in the figure below.

External grounding terminal

WARNING Before turning on the calorimeter, never fail to connect it to the ground.
 Ensure to connect the calorimeter to the ground for stable operation and safety.
Do not connect the grounding wire to a gas pipe.
 Ensure the grounding to be D type grounding or equivalent (less than 100 Ω of the grounding
resistance).
 Use cable lugs for the grounding wire without any slack or tangle for safe connection.
<Need of protective grounding>
Do not cut the grounding wire or disconnect the wire from the grounding terminal.
<Defects in protective functions>
Before starting the calorimeter, check the protective functions for defects. When seeming defects
are found in the protective functions, such as protective grounding, do not start the calorimeter.
<External connection>
Before connecting the calorimeter to the external device, securely connect it to the protective
grounding.

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3 How to Install Calorimeter3-3. How to connect wire

3-3-5. Precautions on electrical work
CAUTION Be careful not to damage the internal electronic circuit when wiring. In addition, be careful not toapply stresses on the calorimeter due to load or installation of cables.
 Do not install the power cables and signal cables in parallel with motor power cables etc. Whenthese cables must be installed in parallel for unavoidable reasons, put the power cables andsignal cables in a metal conduit and connect the conduit to the ground.
 Use ring terminals.
 Use appropriate cables to wire.

Using a stable power supply
Not only when the power is turned on but also when the calorimeter is restarted due to momentary blackout,note that OHC-800 is switched to a warm-up status for 15 minutes and stops measurement for function
check status (See Sections 4.1, "From display just after power-on to measurement start" and 4.4,
"Self-diagnostic function").
To reduce risk of momentary blackout, use a UPS (uninterrupted power supply) or take other appropriate
action.
The calorimeter must be provided with the following power supply.
Power supply
100 VAC ± 10% - 240 VAC ± 10% [AC specification]
voltage(Terminal voltage of 24 VDC ± 10% [DC specification]
the calorimeter)
Up to 40 milliseconds
Example of actions(The calorimeter recovers from
Allowed time of
To ensure continuous operation andmomentary blackouts that last 40
momentary blackout
activation, install a UPS etc. outside themilliseconds or longer by restarting
calorimeter.
itself.)
Do not use it with a power supply of
Example of actions
Otherslarge power load or high-frequency
Use a line filter etc. to avoid the noise
noise.
source if necessary.

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3 How to Install Calorimeter3-3. How to connect wire

Introducing protective measures against lightning
If cables are installed outside the factory/plant, or if internal cables are installed in the same duct as thecables coming from outside the factory/plant, "inductive lightning surge" may be caused by lightning.
Because lightning acts as a large emission source while cables act as a receiving antenna, devices
connected to the cables may be damaged..
The occurrence of lightning cannot be prevented, and even cables installed in a metal conduit or under the
ground cannot be completely protected from inductive lightning surge caused by lightning.
Although complete elimination of damages caused by lightning is impossible, the following protective
measures can be taken.
Take appropriate measures in accordance with the importance of the facilities andthe environment.
Protection against
lightning

Grounding

Provide protection by a surge protective device (cable arrester).
Install a lightning arrester before the field devices and central processing
equipment to mitigate any risk due to inductive lightning surge transmitted
through the cable. For information on how to use a lightning arrester, pleasecontact the manufacturer.
In addition to lightning, there are more sources of surge noise. To protect devices
from these noise sources, the devices must be grounded.

* The surge protective device has a circuit to remove a surge voltage which damages field devices.
Therefore, signals may be attenuated by installing the arrester. Before installing a lightning arrester, verify
that it works properly.

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3 How to Install Calorimeter3-3. How to connect wire

Proper use of contact
If the contact output of this product is used on a line where large inductive load occurs, the following errors
may occur due to counter electromotive force generated at the contact.
 Deposition, defective insulation or defective contact at the relay contact
 Damage of any electric parts due to high-voltage generation
 Abnormal operations by an out-of-control CPU

CAUTION Do not use the contacts of the calorimeter directly for drive control over external devices thatgenerate large inductive load, such as a fluorescent lamp or large-scale motor.
 To control a line where large inductive load occurs, provide an external relay for contact
amplification. However, because the coil of an external relay also involves inductive load, selecta relay at a lower voltage, and then protect the contact of the calorimeter with an appropriate
surge absorbing part, such as a CR circuit.

Coil

Load

To control a line where large inductive load occurs, protect the contacts of this product as shown in the
figure below.

ContactPowersupplyPowersupplyExternal relay(low-voltage relay)* SK1, SK2:

Surge absorbing parts

 Relay it with an external relay (contact amplification). At the same time, the surge absorbing part SK1
suitable for the specifications must be attached to the external relay.
 In addition, the surge absorbing part SK2 must be attached to the loaded side of the external relay ifnecessary.
 It may be recommended that the surge absorbing part should be attached to the contact for certain loadconditions. It must be attached to an appropriate position by checking how the load is activated.

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3 How to Install Calorimeter3-4. How to tube

3-4. How to tube
3-4-1. Sampling device
Use the OHC-800 in combination with asampling device RS-400 series specified by
RIKEN KEIKI (or an equivalent cubicle etc.).
The figure on the right shows a typical internaltubing system of the sampling device RS-400
series.

Unit
UNIT-A

UNIT-B

SymbolV1

Item
Needle valve

V2

Needle valve

CV

V

Switching valve
Pressure
regulator
Pressure
gauge
Flow meterwith needle
valve
Pressure
regulator
Pressure
gauge
Needle valve

CV

Switching valve

RV1

Relief valve
Relief valve

PR
PG
FL

UNIT-CPR
PG

UNIT-D

RV2

Function / Description
Adjusts the flow rate of the measuring gas supplied from
UNIT-B.
Adjusts the flow rate of the reference gas or span gas
supplied from UNIT-C.
Selects a gas to be supplied to the OHC-800.
Adjusts the measurement gas supplied from GAS IN to a
constant pressure.
Indicates the pressure of the measuring gas after pressureadjustment.
Adjusts and indicates the bypass flow rate of the gas
discharged from BYPASS OUT.
Adjusts the reference gas supplied from REF IN to a
constant pressure.
Indicates the pressure of the reference gas after pressureadjustment.
Adjusts the flow rate of the reference gas to be supplied to
the OHC-800.
Switches the gas to be supplied to UNIT-A between thereference gas and span gas.
When the sampling system malfunctions, relieves theexcessive pressure from RELIEF OUT to prevent breakageof the OHC-800.
*) Type without a bypass line is available for UNIT-B.
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3 How to Install Calorimeter3-4. How to tube

3-4-2. Recommended external tubing system
If the sampling point is on a high-pressure line over 0.9 MPa, decompression must be performed outside
the sampling device. Decompression must be performed as close to the sampling point as possible toensure the quickest possible arrival of the measuring gas at the OHC-800. (Use the direct-insertion type ofpressure regulator if possible.)
Since the OHC-800 consumes approximately 300 mL/min of measuring gas, which is small, the bypass flowrate must be increased to ensure quicker arrival of the gas.
If there is a low-pressure line of about 20 kPa, BYPASS OUT can be connected. If there is no low-pressureline, release the gas from BYPASS OUT into the atmosphere.
Since there is no limit on the arrival time of the reference gas, there is no problem unless the pressure
exceeds 0.9 MPa.
The gas from GAS OUT should be released into the atmosphere in principle, but it can be exhaust into an
exhaust duct equivalent to the atmospheric pressure (atmospheric pressure ±3 kPa) if any.
If RELIEF OUT converges on GAS OUT, use tubing with inner diameter of Φ10 mm or more (3/8" or more) if
the length of the tube is 20 m or shorter in order to decrease the load from the converging point todownstream.
The end point of a vent for atmosphere release should form an inverted "T" shape to prevent inflow ofrainwater or variations of exhaust pressure due to wind inflow.

If the length is 20 m or shorter,
the inner diametermust be 10 mm or
longer.

High-pressure line

Low-pressureline
0.02 MPa or less

Reference gas
0.9 MPa Max

Only during
maintenanceIf there is any potential risk of drain or dust inflow, install a trap or filter to prevent inflow of those foreign
substances.

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3 How to Install Calorimeter3-4. How to tube

The table below shows the guideline values for the "setting pressures of external pressure regulator" and"bypass flow rates" corresponding to the "tubing diameters" and "tubing lengths" from the external pressure
regulator to GAS IN of the sampling device in the tubing system shown on the previous page.
Use this table only for your reference because it shows estimated values for assumed arrival time of six
seconds or shorter, without any view for upstream tubing structure from external pressure regulator or filters
installed at any point of the tubing.
Tubing length

10 m

20 m

Φ3, 1/8"

Setting pressure: 0.04 MPa
Bypass: Not required

Setting pressure: 0.2 - 3 MPa
Bypass flow rate: 2 - 5 L/min

Φ6, 1/4"

Setting pressure: 0.1 MPa
Bypass flow rate: 2.5 - 5 L/min

Setting pressure: 0.1 MPa
Bypass flow rate: 5 L/min

Φ8, 5/16"

Setting pressure: 0.1 MPa
Bypass flow rate: 5 - 10 L/min

Setting pressure: 0.1 MPa
Bypass flow rate: 10 L/min

Φ10, 3/8"

Setting pressure: 0.1 MPa
Bypass flow rate: 10 - 20 L/min

Setting pressure: 0.1 MPa
Bypass flow rate: 20 L/min

Tubing diameter

Use tubing with a large inner diameter for GAS OUT and RELIEF OUT.

GAS OUTRELIEF OUT

Φ6-4
5 m or shorter
0.5 m or shorter

Φ8-6
25 m or shorter4 m or shorterΦ10-8----10 m or shorter

3-4-3. Precautions on tubing work
 Use stainless tubing.
 After the tube is cut, its cut point may have a smaller inner diameter.
Use a file etc. to expand the inner diameter of the cut point.
 Cut-dust of tubing may cause failures of the needle valve, flow rate detection mechanism, switchingvalve etc. To remove cut-dust remaining inside of the tube, blow compressed air etc., into the tube before
connecting it to the calorimeter.
 Determine a sampling point inlet for the measuring gas, considering the airflow of the measuring gas line,
unevenness in the manufacturing process of the fuel gas.
 Adjust the measuring gas equivalent to the ambient temperature before supplying it to the sampling
device.

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4 How to Operate in MEASURING MODE

4-1. From display just after power-on to measurement start4

How to Operate in
MEASURING MODE
4-1. From display just after power-on to measurement
start
At power-on, the self-diagnostic function starts, and after the initial screen is displayed for about fiveseconds, the WARM UP screen appears.

Initial screen

About 5seconds

WARM UP screen

For 15 minutes after power-on, the OHC-800 remains in the "warm-up state." The warm-up state isclassified into the "check of functions (FUNCTION CHECK)" category. In the standard setting, the OHC-800
does not perform measurement, and 4 - 20 mA signals are output according to the setting value specified by
the user.
Relatedsections

4.4, "Self-diagnostic function"
5.2.6, "Check of 4 - 20 mA settings"
6.2.3, "4 - 20 mA condition settings"

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4 How to Operate in MEASURING MODE

4-1. From display just after power-on to measurement start

When warm-up is completed, measurement is started. At the start of measurement, the screen shown
below is displayed.

Displays measuring
result.

Displays one of themeasuring results of"CALORIFICVALUE," ''SPECIFICGRAVITY," "WOBBEINDEX" on thescreen.

Displays the unit of
the measurement
value.

Displays the flow rate of the reference gas (REF).
Make adjustment so that the black circle comes
between the two solid lines that represent the upper(right) and lower (left) limits.*
When adjusted to the middle of the scale, the flow rate
is about 10 mL/min.

Displays the flow rate of themeasuring gas (GAS).
Make adjustment so that the black
circle comes between the two solidlines that represent the upper (right)
and lower (left) limits.*
When adjusted to the middle of thescale, the flow rate is about 300
mL/min.

* To perform measurement with a higher accuracy, adjust the black circle to the middle of the scale.

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4 How to Operate in MEASURING MODE

4-2. How to switch display screens

4-2. How to switch display screens
Press the DISP key during measurement to switch the display among "Calorific value," "Density," "WOBBE
index," and "Cyclic display."
Calorific value display

Density display

WOBBE index display

Cyclic display

Although this operation changes the information displayed on the LCD, it is not reflected on 4 - 20 mA
output signals.
4 - 20 mA signal output conditions can be set as described in Section 6.2.3, "4 - 20 mA condition settings,"
for which one of "Calorific value," "Density," and "WOBBE index" can be selected.
Relatedsections

5.2.6, "Check of 4 - 20 mA settings"
6.2.3, "4 - 20 mA condition settings"

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4 How to Operate in MEASURING MODE

4-3. Switching to other mode

4-3. Switching to other mode
During measurement, press and hold the MODE key for three seconds or longer to display the MODE
CHANGE screen.
3 seconds orlongerMEASURING MODE screen

MODE CHANGE screen

In this MODE CHANGE screen, move the cursor (black bar) using the ▲▼ keys to select a desired modeand confirm it using the SET key to enter each mode.
The screen and details of each mode are shown in the table below.
Mode
ScreenDetails
CHECK MODE
Used to display or check the operation status or
setting conditions of each unit while continuingmeasurement.
In this mode, 4 - 20 mA signals are output without
stopping measurement.
Used to specify the settings of the calorimeter such
SETUP MODE
as how to calculate "Calorific value" and "Density"and the condition settings for 4 - 20 mA output
signals.
Prompts the user for password input because
measurement is stopped in this mode.
Used for factory adjustment, maintenance, or
FACTORY MODE
start-up.
This mode is for exclusive use by RIKEN KEIKI andservice engineer designated by RIKEN KEIKI, andnormally must not be operated by the user.
Prompts the user for password input because
measurement is stopped in this mode.
Used to return to the normal MEASURING MODE
MEASURING MODE
screen.

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4 How to Operate in MEASURING MODE

4-4. Self-diagnostic function

4-4. Self-diagnostic function
The OHC-800, having an advanced self-monitoring/diagnostic function compliant with NAMUR NE107(self-monitoring/diagnostic of field devices), performs real-time self-diagnostic and monitoring for devices
classifying the state into four categories shown below.
The table below shows the categories, screens, and state explanation of the device.
Category
FAILURE

ScreenState explanation
An abnormality occurred inside or outside thedevice, and the measuring result and output signal
are not valid.
Contact Output 2 is activated, and the EV2 lamp(red) lights up. 4 - 20 mA signals are output
according to the setting value specified by the user.
(See Section 6.2.3, "4 - 20 mA condition settings (4 –20 mA SETTINGS).")FUNCTION
CHECK

Although the device is normal, measurement is
stopped due to the operation of the check function
etc.
Contact Output 1 is activated, and the EV1 lamp
(orange) lights up. 4 - 20 mA signals are output
according to the setting value specified by the user.
(See Section 6.2.3, "4 - 20 mA condition settings (4 20 mA SETTINGS).")OUT OF
SPECIFICATION

Although the device is normal and measurement is
continued, an out-of-specifications condition isdetected, deteriorating the reliability of measuring
results and output signals.
Contact Output 1 is activated, and the EV1 lamp
(orange) lights up.
4 - 20 mA signals are output as measuring results.

MAINTENANCEREQUIRED

Although the device is normal and valid
measurement is continued, the calorimeter has
detected the progress of a certain deterioration andis requesting for maintenance.
Contact Output 3 is activated, and the EV3 lamp
(green) lights up.
4 - 20 mA signals are output as measuring results.

The contact output and EV lamp operation settings can be changed using the SETUP MODE as describedin Section 6.2.8, "Display and contact operation settings (DISP. & CONTACT SETTINGS)."

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4-5.
Operations
ofand
contacts,
display,
and signal
output44 How
How toto Operate
Operate inin MEASURING
MEASURING MODE
MODE 4-5. Operationsof contacts,
display,
signal output
after recovery
to normal
state
after recovery to normal state

4-5. Operations of contacts, display, and signal output
after recovery to normal stateThis section describes how the OHC-800 operates when it detects one of the state categories shown below
using the self-diagnostic/monitoring function and returns to a normal state by itself.
 FAILURE
 OUT OF SPECIFICATION
 MAINTENANCE REQUIREDIn the standard setting of the OHC-800, the operations of the contacts, LCD display screen, and 4 - 20 mA
signal output are as described below.
<Contact activation>
The contacts are self-latched, and the contact state is maintained after state recovery. To reset the contact
state, enter the CHECK MODE and do as described in Section 5.2.13, "Latching reset for display andcontact (LATCHING RESET (DISP. & CONTACT))."<LCD display screen>
After state recovery, the calorimeter enters the "Trace display" state, in which the display screen
corresponding to the category that has occurred and the display screen for normal measurement are
displayed in turn.
To reset this display state, enter the CHECK MODE and do as described in Section 5.2.13, "Latching resetfor display and contact (LATCHING RESET (DISP. & CONTACT))."

Every 1 second

Operation of "Trace display"<4 - 20 mA signal>
4 - 20 mA signal is self-reset after state recovery, and normal measuring results are output.
Relatedsections

5.2.12, "Check of display and contact settings (DISP. & CONTACT PARAMETER)"
6.2.8, "Display and contact operation settings (DISP. & CONTACT SETTINGS)"* Turning off and on the power resets all of the contact latching states and the LCD "Trace display"
operations.

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55 How
How toto Operate
Operate inin Check
Check Mode
Mode

5How to Operate in CheckMode
The CHECK MODE is used to display or check the operation status or setting conditions of each unit while
continuing measurement. In this mode, 4 - 20 mA signals are output as measuring results without stopping
measurement.
To enter CHECK MODE, display the MODE CHANGE screen while in MEASURING MODE, move thecursor (black bar) using the ▲▼ keys, select "CHECK MODE," and confirm it using the SET key. This
operation displays the menu screen of CHECK MODE. (See Section 4.3, "Switching to other mode.")In the menu screen of CHECK MODE, press and hold the ESC key for three seconds or more to return to
the MEASURING MODE.

3 seconds orlonger
MODE CHANGE
screenMenu screen

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MEASURING MODE

5 How to Operate in Check Mode

5-1. Menu items of CHECK MODE

5-1. Menu items of CHECK MODE
The menu items that can be selected in CHECK MODE are shown in the table below.

Display the state of the
optical sensor unit.

Display the state of thesonic sensor unit.

Display the state of themain controller.

Display the measuringconditions for calorificvalue.

Display the measuringconditions for density.

Display 4 - 20 mA
setting.

Display the pressure
sensor output.

Display the temperature
sensor output.

Display the setting of the Display the setting of the Display the Opt-Sonic
calorific value
density calculation.
calculation process.
calculation.

Display the setting of thedisplay and contacts.

Reset the latching of thedisplay and contacts.

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5 How to Operate in Check Mode

5-2. Items and details

5-2. Items and details
In the menu screen of CHECK MODE, select the desired item using the ▲▼ keys and confirm it using the
SET key to display the detailed information for the item. This section describes the detailed information
displayed for the items.

5-2-1. Check of optical sensor unit state (OPTICAL SENSOR
UNIT CONDITION)
This screen displays the program information for the optical sensor unit, the self-diagnostic results
measured inside the unit etc. in turn.
Displays the program number, SUM number,
Rev number, SPE number, serial number
etc.

Menu screen
Displays the brightness and contrast ofinterference fringes for each of LED1 and
LED2.

Displays the information on the phases ofinterference fringes.

Displays the information on the opticalsensor unit, i.e., used power voltages,
refractive index measuring results, anddriving voltages of LED1 and LED2.

Displays the self-diagnostic flags managed
inside the optical sensor.

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5 How to Operate in Check Mode

5-2. Items and details

5-2-2. Check of sonic sensor unit state (SONIC SENSOR UNIT
CONDITION)
This screen displays the program information for the sonic sensor unit, the self-diagnostic results measured
inside the unit etc.
Displays the program number,
SUM number, andserial number.

Menu screen
Displays the time in which sound arrives,
standardized signal, andself-diagnostic flags(failure and warning flags).

5-2-3. Check of main controller state (MAIN CONTROLLERCONDITION)
This screen displays the program information for the main controller, the self-diagnostic results measured
inside the controller etc.
Displays the program number, SUM number,
Rev number, SPE number, serial number
etc.

Menu screen
Displays the voltages of the power supply
systems (3.3 V, 5 V, and 24 V systems).
Display the output state of 4 - 20 mA signal.

Displays the various self-diagnostic flags
monitored inside the main controller.

Displays the language used for "CAUTION
screen."42 / 87

5 How to Operate in Check Mode

5-2. Items and details

5-2-4. Check of measuring conditions for calorific value(CALORIFIC VALUE PARAMETER)This screen displays the "unit," "calorific value type," "standard temperature," "standard pressure," and"offset value" to be used for calorimetry.
The "offset value" can be changed using the SETUP MODE as described in Section 6.2.7, "Offset(OFFSET ADJUSTMENT)." Contact RIKEN KEIKI if other item settings need to be changed.
Unit of calorimetry
Calorific value type
Standard temperatureStandard pressure
Calorific value offset

Menu screen

5-2-5. Check of measuring conditions for density (DENSITYPARAMETER)This screen displays the "unit," "standard pressure," "standard temperature," and "offset value" to be used
for densimetry.
The "offset value" can be changed using the SETUP MODE as described in Section 6.2.7, "Offset (OFFSET
ADJUSTMENT)." Contact RIKEN KEIKI if other item settings need to be changed.
Unit of densimetryStandard temperatureStandard pressure
Density offset
Menu screen

5-2-6. Check of 4 - 20 mA settings (4 - 20 mA PARAMETER)This screen displays the "output item" and "output range" to be output in 4 - 20 mA signal.
It also displays the settings of 4 - 20 mA signal for a FAILURE or FUNCTION CHECK. (* HOLD
MEASURED VALUE means that the last measured value is held and output.)
The figure below shows that the output item is set to "CALORIFIC VALUE" and the output range to "36.00 to
46.00 MJ/m3" and that the output item is fixed to 0.50 mA for FAILURE and the last measured value is held
and output for FUNCTION CHECK.
Output item
Output range
4 - 20 mA setting for FAILURE
4 - 20 mA setting for FUNCTION CHECK
Menu screen
Note that 20 mA is output if the detected result exceeds the upper limit of the output range setting and that 4
mA is output if it falls below the lower limit.

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5 How to Operate in Check Mode

5-2. Items and details

5-2-7. Check of pressure sensor output (PRESSURE SENSORREADINGS)This screen displays the output of three pressure sensors installed in the optical sensor unit.
P (GAS): Output of the micro-differential pressure sensor that detects the flow rate of measuring
gas supplied to the OHC-800.
P (REF): Output of the micro-differential pressure sensor that detects the flow rate of REF gas
supplied to the OHC-800.
P (OUT): Output of the absolute pressure sensor at GAS OUT of the OHC-800 to be used forpressure correction.
 Output value of GAS differential pressure
sensor Output value of REF differential pressure
sensor Output value of OUT absolute pressure
sensorMenu screen

5-2-8. Check of temperature sensor output (TEMPERATURESENSOR READINGS)
This screen displays the output of temperature sensors installed in the main controller, optical sensor unit,
and sonic sensor unit.
 Output value of temperature sensor on
main PCB Output value of temperature sensor on
optical sensor unit
 Output value of temperature sensor onsonic sensor unit

Menu screen

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5 How to Operate in Check Mode

5-2. Items and details

5-2-9. Check of calorific value calculation settings(CALCULATION FACTOR (CALORIFIC VALUE))
This screen displays the setting of the calorific value calculation type. The following three types of calorificvalue calculation are available.
OPT-SONIC CALCULATION:
OPTICAL SENSOR:SONIC SENSOR:

Calculate the calorific value using a combination of the optical and sonicsensors.
Calculate the calorific value using only the optical sensor.
Calculate the calorific value using only the sonic sensor.

For information on the differences of these types and change of settings, see the SETUP MODE describedin Section 6.2.1, "Setting of calorific value calculation conditions (CALCULATION FACTOR (CALORIFICVALUE))."
If OPT-SONIC CALCULATION is selected,
the calculation factor α is displayed.

Menu screen

5-2-10. Check of density calculation settings (CALCULATIONFACTOR (DENSITY))
This screen displays the setting of the density calculation type. The following three types of density
calculation are available.
OPT-SONIC CALCULATION:
OPTICAL SENSOR:SONIC SENSOR:

Calculate the density using a combination of the optical and sonicsensors.
Calculate the density using only the optical sensor.
Calculate the density using only the sonic sensor.

For information on the differences of these types and change of settings, see the SETUP MODE describedin Section 6.2.2, "Setting of density calculation conditions (CALCULATION FACTOR (DENSITY))."
If OPT-SONIC CALCULATION is selected,
the calculation factor β is displayed.

Menu screen

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5 How to Operate in Check Mode

5-2. Items and details

5-2-11. Check of Opt-Sonic calculation process (OPT-SONICREADINGS)This screen displays the interim result of the Opt-Sonic calculation.

Menu screen
The items to be displayed are as shown below.
SymbolMeaning of symbol
αFactor used in the calorific value calculation of Opt-Sonic calculation
H(OPT)
Calorific value measured using only the optical sensor
H(SONIC)
Calorific value measured using only the sonic sensor
H(OUT)
Result obtained using the method selected in the "calorific value calculation setting"β
Factor used in the density calculation of Opt-Sonic calculation
S(OPT)
Density measured using only the optical sensor (converted to specific gravity)
S(SONIC)
Density measured using only the sonic sensor (converted to specific gravity)
S(OUT)
Result obtained using the method selected in the "density calculation setting"Regardless of the settings of the product, this screen displays a calorific value converted to MJ/m3, Gross,
0°C, and 101.325 kPa and a density converted to a specific gravity (AIR=1), respectively.

5-2-12. Check of display and contact settings (DISP. &CONTACT PARAMETER)This screen displays how the LCD display and contacts operate according to the conditions applied when
the OHC-800 detects either of the FAILURE, FUNCTION CHECK, OUT OF SPECIFICATION, andMAINTENANCE REQUIRED states.
In the menu screen, press the SET key to display the list of conditions of the self-diagnostic/monitoring
function. Using the ▲▼ keys, select a condition and press the SET key to display the LCD display andcontact operations when the selected condition is detected.
For information on how to change the settings and available operations, see the SETUP MODE describedin Section 6.2.8, "Setting of display and contact operations (DISP. & CONTACT SETTINGS)."
The self-diagnostic conditions are displayed.
Select an item using ▲▼ keys and press the
SET key to check the details.

Menu screen
The details of LCD display and contact
operation under the self-diagnostic
conditions are displayed.

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5 How to Operate in Check Mode

5-2. Items and details

5-2-13. Latching reset for display and contact (LATCHINGRESET (DISP. & CONTACT)) FAILURE
 OUT OF SPECIFICATION
 MAINTENANCE REQUIRED
If the OHC-800 detects one of the state categories shown above using the self-diagnostic/monitoring
function and returns to a normal state by itself, the contact is self-latched and the LCD display screen entersthe "Trace display" state in its standard settings. (See Section 4.5, "Operations of contacts, display, andsignal output after recovery to normal state.")Every 1 second

Operation of "Trace display"
This menu item is used to reset the self-latch state of the contacts and the "Trace display" state of the LCD
display.
In the menu screen, press the SET key to display the CAUTION screen informing that the latching states ofthe display screen and contacts will be reset.
When "OK" is selected using the ▲▼ + SET keys, the states of the contacts and LCD are reset, and theordinary measurement screen and the normal contact operation are resumed.

Menu screen

CAUTION screen(English)47 / 87

CAUTION screen(Chinese)

CAUTION screen(Japanese)

6 How to Operate in SETUP MODE

6

How to Operate in SETUP
MODE
SETUP MODE is used to set how to calculate calorific value and density, output conditions for 4 - 20 mA
signals, operating conditions of the contacts, etc with the OHC-800.
In this mode, the calorimeter stops measurement, enters the "FUNCTION CHECK" state, and outputs 4 - 20
signals according to the user-specified conditions.
(For information on changing the output conditions, see Section 6.2.3, "4 - 20 mA condition settings (4 - 20
mA SETTINGS).")To enter SETUP MODE, display the MODE CHANGE screen while in MEASURING MODE, move thecursor (black bar) using the ▲▼ keys, select "SETUP MODE," and press the SET key to confirm it. Then,the password input screen is displayed, so enter the password (one character after another) using the ▲▼+ SET keys.
The password is factory-set to "00000." For information on how to change the password, see the SETUP
MODE described in Section 6.2.13, "Password change (PASSWORD SETUP (SETUP MODE))."

MODE CHANGE screen

Password input screen

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6 How to Operate in SETUP MODE
When a correct password is entered, the "CAUTION screen" is displayed to inform that measurement will
be stopped.
When "OK" is selected using the ▲▼ + SET keys, measurement is stopped, and the menu screen for the
SETUP MODE is displayed.
In the menu screen of SETUP MODE, press and hold the ESC key for three seconds or more to return to
the MEASURING MODE.

CAUTION screen (English)

CAUTION screen (Chinese)

CAUTION screen (Japanese)

3 seconds
or longer

Menu screen

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MEASURING MODE

6 How to Operate in SETUP MODE

6-1. SETUP MODE items

6-1. SETUP MODE items
In the SETUP MODE, the menu items shown in the table below can be used.

Setting of calorific value
calculation conditions

Setting of density calculation
conditions

Setting of 4 - 20 mA conditions

Set the detailed conditions forcalorific value calculation such assonic sensor measurement,
optical sensor measurement, and
Opt-Sonic calculation.

Set the detailed conditions fordensity calculation such as sonicsensor measurement, opticalsensor measurement, and
Opt-Sonic calculation.

Set the details of information to
be output in 4 - 20 mA signals.

4 - 20 mA output adjustment

4 - 20 mA output test

Reference calibration

Adjust 4 - 20 mA signal output
level.

OffsetAdjust the offset value to be
added to or subtracted from themeasuring results of calorificvalue or density.

Change of RS-485 (MODBUS)
communication settings
Set the RS-485 (MODBUS)
communication conditions.

Password change
Change the password required toenter SETUP MODE.

Output an arbitrary test signal for
4 - 20 mA signals.

Display/contact operation
settings

Perform reference calibration.
Reference calibration is
operation for adjusting thereference point of the opticalsensor unit.

Change of LCD display settings

Set the details of display and
Set the contrast of LCD display
contact operations whenand brightness of backlight.
detecting a certain condition
using the self-diagnostic function.

Change of energized contact
settings

Check the contact operation

Set the energized contact
conditions for Contact Outputs 1
through 3.

Output an arbitrary test signal forcontact signal.

Log data download
Download the log data using
IrDA.

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6 How to Operate in SETUP MODE

6-2. Items and details

6-2. Items and details
6-2-1. Setting of calorific value calculation conditions(CALCULATION FACTOR (CALORIFIC VALUE))
Set the calorific value calculation conditions. In the menu screen, press the SET key to display the setting
value check screen and display the current settings of calculation conditions. Next, press the SET key tohighlight the line indicating the calculation method in reverse video and enable selection of a calculation
method using the ▲▼ + SET keys.

Menu screen

Setting value check
screenInput screen

The figures above are examples in which Opt-Sonic calculation is set. The available calculation methods
and characteristics are shown in the table below.

Opt-Sonic calculation

Optical sensor calculation

Sonic sensor calculation

This method effectively suppresses the influences ofinterference gases on the measuring results of the optical andsonic sensors through calculation processing.
The calculation factor α must be set according to the major
fluctuating components of interference gases.
This method calculates calorific values using only the opticalsensor. The calorific value measurement using only the opticalsensor is relatively less influenced by interference gases.
Therefore, this method can also be used for measurement if
there is a small amount of interference gases.
This method calculates calorific values using only the sonicsensor. The calorific value measurement using only the sonicsensor is significantly influenced by interference gases.
Therefore, this method is not recommended unless there areunavoidable circumstances.

After "OPT-SONIC CALCULATION" is selected as the calorific value calculation method, the calculation
factor α setting screen is displayed. Set a numeric value using the ▲▼ keys, and confirm the value using
the SET key.

Input numeric values
using ▲▼ keys

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6 How to Operate in SETUP MODE

6-2. Items and details

6-2-2. Setting of density calculation conditions (CALCULATIONFACTOR (DENSITY))
Set the density calculation conditions. In the menu screen, press the SET key to display the setting value
check screen and display the current settings of calculation conditions. Next, press the SET key to highlightthe line indicating the calculation method in reverse video and enable selection and confirmation of acalculation method using the ▲▼ + SET keys.

Menu screen

Setting value check
screenInput screen

The figures above are examples in which Opt-Sonic calculation is set. The available calculation methods
and characteristics are shown in the table below.

Opt-Sonic calculation

This method effectively suppresses the influences of interference
gases on the measuring results of the optical and sonic sensors
through calculation processing.
The calculation factor β must be set according to the major
fluctuating components of interference gases.
This method calculates density using only the optical sensor. The
density measurement using only the optical sensor is significantly
influenced by interference gases. Therefore, this method is notrecommended unless there are unavoidable circumstances.

Optical sensor calculation

Sonic sensor calculation

This method calculates density using only the sonic sensor. The
density measurement using only the sonic sensor is relatively
less influenced by interference gases. Therefore, this method canalso be used for measurement if there is a small amount ofinterference gases.

When "OPT-SONIC CALCULATION" is selected as the density calculation method, the calculation factor βsetting screen is displayed. Set a numeric value using the ▲▼ keys, and confirm the value using the SET
key.

Input numeric values
using ▲▼ keys

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6 How to Operate in SETUP MODE

6-2. Items and details

6-2-3. 4 – 20 mA condition settings (4 – 20 mA SETTINGS)
Display the output conditions of 4 - 20 mA signal. In the menu screen, press the SET key to display thesetting value check screen and display the current settings of 4 - 20 mA conditions.

Menu screen

Setting value check
screenThe example above shows the screens displayed when "CALORIFIC VALUE" is the selected output item,
and the 36.00 to 46.00 MJ/m3 range is the output range setting of 4 - 20 mA signals.
When the SET key is pressed in the setting value check screen, the "CAUTION screen" is displayed to
inform that 4 - 20 mA output signal will be changed.

CAUTION screen(English)

CAUTION screen(Chinese)

CAUTION screen(Japanese)

When "OK" is selected using the ▲▼+SET keys, and the setting screen appears. As shown in the figure
below, use the ▲▼ and SET keys to specify the output item, upper and lower limits of the output range, andoutput values for the FAILURE and FUNCTION CHECK states.

Setting of output item

Setting of lower limit ofoutput range

Setting of output value
for FAILURE

Setting of output value for
FUNCTION CHECK

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Setting of upper limit ofoutput range

6 How to Operate in SETUP MODE

6-2. Items and details

6-2-4. 4 – 20 mA output adjustment (4 – 20 mA ADJUSTMENT)
Adjust 4 - 20 mA signal output level. When the SET key is pressed in the menu screen, the "CAUTION
screen" is displayed to inform that 4 - 20 mA output signal will be changed.

Menu screen

CAUTION screen(English)

CAUTION screen(Chinese)

CAUTION screen(Japanese)

When "OK" is selected using the ▲▼+SET keys, the test signal output screen appears, and a 4 mA or 20
mA test signal is output.
Using the ▲▼ keys, select one of the test signals to output and press the SET key to highlight the line
indicating the PWM value in reverse video and enable selection of an output level. Using the ▲▼ keys,
change the PWM value to adjust the output level, and press the SET key to confirm it.

Test signal output screen

Output adjustment screen

Test signal output screen

Output adjustment screen

Press the ESC key to finish adjustment and return to the menu screen. 4 - 20 mA output value returns to thestate before the output test.

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6 How to Operate in SETUP MODE

6-2. Items and details

6-2-5. 4 – 20 mA output test (4 – 20 mA TEST)This screen is used to output an arbitrary test signal for 4 - 20 mA signals. When the SET key is pressed in
the menu screen, the "CAUTION screen" is displayed to inform that 4 - 20 mA output signal will be changed.

Menu screen

CAUTION screen(English)

CAUTION screen(Chinese)

CAUTION screen(Japanese)

When "OK" is selected using the ▲▼ + SET keys, the 4 mA test signal is output.
Further press the ▲▼ keys to change the test signal from 0.50 to 22.00 mA in steps of 0.05 mA.

Press the ESC key to finish output test and return to the menu screen. 4 - 20 mA output value returns to thestate before the output test.

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6 How to Operate in SETUP MODE

6-2. Items and details

6-2-6. Reference calibration (REF. CALIBRATION)
Perform reference calibration if there is a deviation in the reference point for measurement by the opticalsensor unit.
In the menu screen, press the SET key to display the reference calibration check screen.

NOTE
A sufficient amount of reference gas must be supplied from the measuring gas IN of the calorimeter toperform reference calibration.

Menu screen

Check screen

In this state, supply a sufficient amount of reference gas from the OHC-800 measuring gas IN to check the
PHASE θALL value. Reference gas calibration is not needed if the PHASE θALL value is near 0 (e.g.,±0.0100 or less).
To perform reference gas calibration, select REF.CALIB. using the ▲▼ keys and confirm it using the SET
key.

When calibration is completed in about three seconds, the check screen appears again. Check that the
PHASE θALL value is near 0 (e.g. ±0.0100 or less).
Press the ESC key or select CANCEL to end the operation.

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6 How to Operate in SETUP MODE

6-2. Items and details

6-2-7. Offset (OFFSET ADJUSTMENT)
Adjust the offset value to be added to or subtracted from the measuring results of calorific value or density.
Use this function if there is a difference between the measuring results of the OHC-800 and those of thecalorimeter/densiometer that the user uses as the criteria or those of the standard gas.
In the menu screen, press the SET key to display the setting value check screen and display the current
settings of offset values. Next, press the SET key to display the input screen and enter and confirm theoffset values for the calorific value and density in turn using the ▲▼ and SET keys.

Menu screen

Setting value check
screenInput screen

Input screen

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6 How to Operate in SETUP MODE

6-2. Items and details

6-2-8. Display and contact operation settings (DISP. &CONTACT SETTINGS)
Set the operations of LCD display and contacts in detail according to the conditions applied when the
self-diagnostic/monitoring function detects either of the FAILURE, FUNCTION CHECK, OUT OF
SPECIFICATION, and MAINTENANCE REQUIRED states.
In the menu screen, press the SET key to display the list of conditions of the self-diagnostic/monitoring
function.
Using the ▲▼ keys, select a condition and press the SET key to display the details screen, which displays
the LCD display and contact operations that occur when the selected condition is detected.

Menu screen

Condition list screen

Details screen

In the details screen, press the SET key to highlight an item to be changed in reverse video. Using the ▲▼keys, select an operation and confirm it using the SET key. The table below shows the operations that canbe selected for the items.
Item to be changed

DISPLAY(LCD display operation)w

Change of contact
operation

Available
operation
TRACE DISP

After state recovery, displays data in turn to keep thehistory of the states that occurred.

AUTO RESET

After state recovery, returns to the normal measurement
screen.

OFF

Data according to the states is not displayed even if any
state has occurred.

LATCHING

Maintains the contact state after state recovery.

AUTO RESET

Automatically resets the contact state after state
recovery.

OFF

Contacts are not operated even if any state has
occurred.

CONT.-1
CONT.-2
CONT.-3
Change of contact
position

Description

OFF

Output to Contact 1.
Output to Contact 2.
Output to Contact 3.
Contacts are not operated even if any state has
occurred.

NOTE
The FAILURE screen is not displayed even if an abnormality occurs for an item with DISPLAY turned OFF.
Therefore, 4 - 20 mA output value is not set to a FAILURE state as well and the measurement is continued.

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6 How to Operate in SETUP MODE

6-2. Items and details

6-2-9. LCD display settings (LCD DISPLAY SETTINGS)
Change the contrast setting of LCD display and brightness setting of backlight. In the menu screen, press
the SET key to display the setting value check screen and display the current settings of communication
conditions.
Next, press the SET key to display the input screen and enter and confirm the contrast and brightness inturn using the ▲▼ and SET keys.

Menu screen

Setting value check
screenCAUTION
Changing the contrast significantly at once may make the screen entirely white (or entirely black),
causing a problem in the operations thereafter. The contrast setting must be changed little by little.

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6 How to Operate in SETUP MODE

6-2. Items and details

6-2-10. RS-485 (MODBUS) communication settings(RS-485(MODBUS) SETTINGS)
Change the RS-485 (MODBUS) communication settings. In the menu screen, press the SET key to display
the setting value check screen and display the current settings of communication conditions. Next, press
the SET key to display the input screen and highlight the items in reverse video in turn from the baud rate.
Using the ▲▼ and SET keys, select and confirm a condition for each of the items.

Menu screen

Setting value check
screenInput screen

The available value settings for each of the items are as shown below.
[Baud rate]
4800 bps, 9600 bps,
19200 bps, 38400 bps,
57600 bps, and 115200
bps[Data bit]
7-BIT and 8-BIT[Stop bit]
1-BIT, 2-BIT, ... NONE

[Parity bit]
NONE (No parity)
IGNORE (Ignore parity)
EVEN (Even number),andODD (Odd number)

Parity bit[Machine ID]
1 - 31NOTE
If you are considering the use of the RS-485 (MODBUS) communication function, contact RIKEN KEIKI.

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6 How to Operate in SETUP MODE

6-2. Items and details

6-2-11. Change of energized contact settings (CONTACTSETTINGS)
Change the energized contact settings for Contact Outputs 1 through 3. In the menu screen, press the SET
key to display the setting value check screen and display the current settings of energized contacts. Next,
press the SET key to display the input screen and highlight one of the energized contact conditions inreverse video in turn, starting from Contact Output 1 (CONT.-1).
Using the ▲▼ and SET keys, select and confirm one of the conditions, DE-ENERGIZED (De-energized at
all times) and ENERGIZED (Energized at all times).

Menu screen

Setting value check
screenInput screen

6-2-12. Check the contact operation (CONTACT TEST)
Output an arbitrary test signal for contact signal. In the menu screen, press the SET key to display“CAUTION screen” informing that a contact signal will change.

Menu screen

CAUTION screen(English)

CAUTION screen(Chinese)

CAUTION screen(Japanese)

Select the “OK” using ▲▼+SET key to display the test signal output screen, the current contact setting
appears, at the same time the test signal of contact signal is delivered.
Press the SET key to be in contact select screen, and contact number is displayed inverted. Using the ▲▼keys to select which test signal to be changed, from contact 1 to cotact 3. In addition, press SET key andoutput change screen, using ▲▼ key to change the contact setting ACTIVE/NORMAL.

Test signal output
screenContact select screen

Output change screen

Press the ESC key to finish contact output test and return to the menu screen. Contact output value returns
to the state before the output test.

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6 How to Operate in SETUP MODE

6-2. Items and details

6-2-13. Password change (PASSWORD SETUP (SETUP MODE))
Change the password required to enter SETUP MODE. In the menu screen, press the SET key to display
the setting value check screen and display the current password setting. Next, press the SET key to display
the password input screen and enter characters 0 to 9 and A to F one by one using the ▲▼ and SET keys.

Menu screen

Setting value check
screenInput screen

CAUTION
Note that you cannot enter the SETUP MODE without the password specified here. If you forget the
password, contact RIKEN KEIKI.

6-2-14. Log data download (IrDA COMMUNICATION)
Using IrDA, and perform downloading log data. When enter into this screen, data logging function stops
temporarily. In the menu screen, press the SET key to display the STANDBY screen. The timing is off,
display the CAUTION screen as the following screen. During the log data writing, it cannot download.
Perform 10 to 30 seconds later, again.

Menu screen

STANDBY screen

CAUTION screen

Prepare for a communication equipment (GX-2009 TYPE-DL etc.) in STANDBY screen state.
After start communicating in communication device, select the START using ▲▼ key, and press SET key.
If communications establish normally, it is to be data transmission screen automatically and answer torequest-to-send from communication device. When communications do not establish, whencommunications is interrupted, when ESC key is pressed during communications, when all communications
end and data transmission request-to-send run out, resume STANDBY screen.

STANDBY screen

Confirmed
communication
screenData transmission
screenNOTE
It is optional service to download and analyze log data, and exclusive jigs are necessary. As for details,
refer to 7-3 and contact RIKEN KEIKI.

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7 Maintenance7-1. Maintenance intervals and items

7

Maintenance7-1. Maintenance intervals and items
There are two types of maintenance to be performed by the user, "daily maintenance" and "monthly regular
maintenance" and one type of maintenance to be performed by RIKEN KEIKI service engineer, "biannual
regular maintenance."

7-1-1. Daily maintenance
Daily maintenance is performed to check the soundness of the product operations. Perform daily
maintenance according to the maintenance items and criteria shown in the table below.
Maintenance item

Criteria

 POWER lamp

In a normal state, the POWER lamp remains ON at all times.
Check that the light remains ON normally.

 Lamp1, Lamp2, and Lamp3

In a normal state, the Lamp1, Lamp2, and Lamp3 remain OFF at
all times. Check that these lamps remain OFF.
Check that the LCD does not display FAILURE, OUT OF
SPECIFICATION, MAINTENANCE REQUIRED etc.

 LCD display
 Reference gas (REF) andmeasuring gas (GAS) flow
rates

Check that the black circles that indicate the reference gas(REF) and measuring gas (GAS) flow rates stay between thetwo solid lines that represent the upper and lower limits.

If some kind of abnormal state is found, perform investigation and maintenance according to thetroubleshooting procedures.

Ⅱ2G Ex dbⅡB+H2 T4 Gb

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7 Maintenance7-1. Maintenance intervals and items

7-1-2. Monthly regular maintenance
Monthly regular maintenance is performed to check the soundness of the exposition-proof performance.
Perform monthly regular maintenance according to the maintenance items and criteria shown in the tablebelow.
Maintenance item

Criteria

 Casting enclosure Clamping screws and bolts

Is there any abnormality or damage on the enclosure?

 Explosion-proof certification

Is there any abnormality on the nameplate on which a model
examination certificate mark is printed?
Is there any crack, discoloration, or deformation on the transparent
window?



nameplate
Transparent window Grounding terminal
 Cable glandIs there any abnormality such as looseness or loss of clamping
screws and bolts?

Is there normal wire connection to the grounding terminal?
Is there any abnormality on the cable gland or wiring?

wiring

①
②

③

④

⑤

⑥

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7 Maintenance7-1. Maintenance intervals and items

7-1-3. Biannual regular maintenance
Biannual regular maintenance is performed to check the soundness of the sensor output, power voltage,
contact output, analog signal output etc. As required, perform the items shown below.
(1) Device cleaning(2) Parts replacement(3) External tubing parts replacement(4) Reading operation check(5) Log data analysis (optional service) (6) Others
At the biannual regular maintenance, the items of daily maintenance and monthly regular maintenance arealso checked.

NOTE
Log data analysis (optional service)
The OHC-800, having an advanced self-monitoring/diagnostic function, monitors the soundness of theitems shown below at all times.
 Light source brightness
 Contrast
 Unit temperatures
 GAS OUT absolute pressure fluctuation
 GAS flow rate REF flow rate Various fault flag Sensor voltage
 4 - 20 mA output state Optical sensor unit output
 Sonic sensor unit output

The product stores at all times the log data that records the "operation statuses" and "diagnostic results"
for more than one year in the past.
In "log data analysis," an optional service, RIKEN KEIKI service engineer collects this log data via IrDA
communications, and RIKEN KEIKI analyzes the data, graph the "operation statuses" and "self-diagnosic
results" for the past one year, and submits a report about them.
The analysis results available in this service, based on long-term data over the past one year, can beused as effective data by the user to check the stability of devices throughout the year and evaluate theplant operation statuses, which cannot be easily done in ordinary biannual regular maintenance.
If you are considering the use of this service, contact RIKEN KEIKI.

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7 Maintenance7-2. Recommended regular replacement parts

7-2. Recommended regular replacement parts
OHC-800
Recommended regular
Average ambient
temperature
replacement parts
Less than 50°C
None
50°C or morePower terminal unit
This product has a design lifetime of 10 years.

Replacement
intervals—
5 years

The filters etc. used in the sampling device and its surroundings must be replaced as needed.

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8 Storage, Relocation, and Disposal

8-1. Procedures to store the calorimeter or leave it for a long time

8

Storage, Relocation, andDisposal
8-1. Procedures to store the calorimeter or leave it fora long time
To leave the OHC-800 and sampling device unused for a middle or long term without removing tubing orcables, it is sufficient to stop supplying the power and measuring and reference gases.
To store them in a warehouse etc. for a long term after removing the tubing and cables, it is necessary tostore them at normal temperatures and humidities where they are not exposed to direct sunlight.
In either case, keep the front and other lids of the OHC-800 enclosure closed so that the explosion-proof
joint surface is not damaged.

8-2. Procedures to relocate the calorimeter or use itagain
To resume using the calorimeter after reconnecting the tubing and cables, request RIKEN KEIKI to start up
the device. When the procedure involves only the resupply of the power and measuring and reference
gases, contact RIKEN KEIKI if required.

CAUTION
When the OHC-800 is relocated, perform external output 4-20mA according to “6.2.4 4-20mA output
adjustment” in connecting the upper system.

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8 Storage, Relocation, and Disposal

8-3. Disposal of products

8-3. Disposal of products
When the OHC-800 is disposed of, it must be treated properly as an industrial waste in accordance with thelocal regulations and other requirements.
Before disposing of the OHC-800, remove the following coin-type battery installed in it.
Specifications of coin-type lithium manganese dioxide battery
Product name:
CR1220Nominal voltage:
3V
Standard capacity: 36 mAh
Removal procedure
Remove the main controller unit. The battery is located in theback of the unit as shown in the figure on the right. A resincase covers the battery. Since the resin case is bonded to the
PCB, remove it using a pair of pliers, flat-blade screwdriver etc.
Slide the battery sideways to remove it. Dispose of theremoved battery after wrapping insulating tape around it.
Located on the back of this location

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9 Troubleshooting

9-1. <FAILURE>

9

Troubleshooting
The information in this chapter is provided to help identify the state of the product from the display on the
OHC-800 and trace down the cause of a trouble etc. This chapter does not describe all the symptoms that
may be encountered although efforts are made to include as many symptoms as possible. If the cause
cannot be identified using the information in this chapter, contact RIKEN KEIKI.

9-1. <FAILURE>

Ⅱ2G Ex dbⅡB+H2 T4 Gb

Display

State explanation

Main cause and required action

Main controller:
ROM abnormality

An abnormality in the main controller ROM.
The main controller must be replaced.

Main controller:
RAM abnormality

An abnormality in the main controller RAM.
The main controller must be replaced.

Main controller:
FRAM abnormality

An abnormality in the main controller FRAM.
The main controller must be replaced.

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9 Troubleshooting
Display

9-1. <FAILURE>
State explanation

Main cause and required action

Main controller:
Abnormal temperaturedetected

Unless an abnormality is found in the installation
environment, a malfunction of the main controller
is suspected.

Main controller:
Supply power abnormality
detected

Unless an abnormality is found in the OHC-800
supply power, a malfunction of the power
terminal unit or main controller is suspected.

Main controller:
Optical sensor unit
abnormality detected

A malfunction of the connecting cable between
the main controller and the optical sensor unit or
the optical sensor unit is suspected.

Main controller:
Sonic sensor unit
abnormality detected

A malfunction of the connecting cable between
the main controller and the sonic sensor unit or
the sonic sensor unit is suspected.

Main controller:
4 - 20 mA output signal
abnormality detected

Unless an abnormality such as a break in 4 - 20mA cable is found, a malfunction of the power
terminal unit or main controller is suspected.

Optical sensor unit:
ROM abnormality detected

An abnormality in the optical sensor unit ROM.
The optical sensor unit must be replaced.

Optical sensor unit:
RAM abnormality detected

An abnormality in the optical sensor unit RAM.
The optical sensor unit must be replaced.

Optical sensor unit:
An abnormality in the optical sensor unit FRAM.
FRAM abnormality detected The optical sensor unit must be replaced.

Optical sensor unit:
Temperature abnormality
detected

Unless an abnormality is found in the installation
environment, a malfunction of the optical sensor
unit is suspected.

Optical sensor unit:
GAS OUT abnormal
absolute pressure detected

Unless an abnormality in the GAS OUT exhaustenvironment or tubing such as clogging is found,a malfunction of the optical sensor unit issuspected.

Optical sensor unit:
Supply power abnormality
detected

Unless an abnormality is found in the OHC-800
supply power, a malfunction of the power
terminal unit or optical sensor unit is suspected.

Optical sensor unit:
Abnormally low brightnessof interference fringe image
data detected

A damage of the optical sensor unit due toinhalation of foreign substances or wastematerials is suspected.

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9 Troubleshooting
Display

9-1. <FAILURE>
State explanation

Main cause and required action

Optical sensor unit:
Abnormally low contrast ofinterference fringe image
data detected

A damage of the optical sensor unit due toinhalation of foreign substances or wastematerials is suspected.

Optical sensor unit:
Reference gas flow rateabnormality detected

Unless a significantly low or high supply volume
is found, clogging or leak of a flow path in andout of the product is suspected.

Optical sensor unit:
Measuring gas flow rateabnormality detected

Unless a significantly low or high supply volume
is found, clogging or leak of a flow path in andout of the product is suspected.

Optical sensor unit:
Out-of-detection-range
measuring gas detected

Unless an abnormality in the composition of themeasuring gas is found, a malfunction of the
optical sensor unit is suspected.

Sonic sensor unit:
Measuring sound pressure
abnormality detected

A damage of the sonic sensor unit due toinhalation of foreign substances or wastematerials is suspected.

Sonic sensor unit:
ROM abnormality detected

An abnormality in the sonic sensor unit ROM.
The sonic sensor unit must be replaced.

Sonic sensor unit:
RAM abnormality detected

An abnormality in the sonic sensor unit RAM.
The sonic sensor unit must be replaced.

Sonic sensor unit:
EEP-ROM abnormality
detected

An abnormality in the sonic sensor unit
EEP-ROM. The sonic sensor unit must be
replaced.

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9 Troubleshooting

9-2. <OUT OF SPECIFICATION>

9-2. <OUT OF SPECIFICATION>

Ⅱ2G Ex dbⅡB+H2 T4 Gb

Display

State explanation

Main cause and required action

Sonic sensor unit:
Out-of-measurement-range measuring gas
detected

Check that the conditions
specified in the "Measuring gas
specification sheet" are met.

Sonic sensor unit:
Out-of-specification temperature detected

Reconsider the operating
environment.

Optical sensor unit:
Out-of-measurement-range measuring gas
detected

Check that the conditions
specified in the "Measuring gas
specification sheet" are met.

Optical sensor unit:
Out-of-defined-range reference gas flowrate detected

Adjust the reference gas flowrate so that the black circle
comes between the two solidlines that represent the upperand lower limits.

Optical sensor unit:
Out-of-defined-range measuring gas flowrate detected

Adjust the measuring gas flowrate so that the black circle
comes between the two solidlines that represent the upperand lower limits.

Optical sensor unit:
Sudden change in GAS OUT absolutepressure detected

Reconsider the GAS OUT
exhaust destination or the GAS
OUT diffusion structure.

Optical sensor unit:
Out-of-measurement-range GAS OUT
absolute pressure detected

Check the absolute pressure of
the GAS OUT exhaust line and
the GAS OUT tubing forabnormality.

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9 Troubleshooting
Display

9-2. <OUT OF SPECIFICATION>
State explanation

Main cause and required action

Optical sensor unit:
Sudden temperature change detected

Reconsider the operating
environment.

Optical sensor unit:
Out-of-specification temperature detected

Reconsider the operating
environment.

Out-of-specification Opt-Sonic:
Calculation results Calorific value anddensity (specific gravity) detected

Check that the conditions
specified in the "Measuring gas
specification sheet" are met.

Main controller:
4 - 20 mA signal output failure detected

Check that the use method
meets the wire connection
method and load resistance(300 Ω at the maximum)
conditions.

Main controller:
Out-of-specification power supply detected

Check whether the power
supplied to the OHC-800 meetsthe required specifications.

Main controller:
Out-of-specification temperature detected

Reconsider the operating
environment.

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9 Troubleshooting

9-3. <MAINTENANCE REQUIRED>

9-3. <MAINTENANCE REQUIRED>Ⅱ2G Ex dbⅡB+H2 T4 Gb

Display

State explanation

Main cause and required action

Sonic sensor unit:
Detected low sound pressure within
permissible range

The sonic sensor contamination
or deterioration has progressed.
The sonic sensor unit must be
replaced.

Optical sensor unit:
Detected drifting within permissible range

In SETUP MODE, performreference calibration.

Optical sensor unit:
Detected low contrast of interference
fringes within permissible range

The optical sensor
contamination or deterioration
has progressed. The opticalsensor unit must be replaced.

Optical sensor unit:
Detected low brightness of interference
fringes within permissible range

The optical sensor
contamination or deterioration
has progressed. The opticalsensor unit must be replaced.

Detected failure of sensor unit disabled due Since other devices may be
to calculation conditions of calorific value or adversely influenced, it isdensity
recommended to investigate thecause and perform required
action for it.
Main controller:
Indicates that the factory adjustment is notcompleted.

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Not displayed for a shipped
product ordinarily.

9 Troubleshooting

9-4. <FUNCTION CHECK>

9-4. <FUNCTION CHECK>Ⅱ2G Ex dbⅡB+H2 T4 Gb

Display

State explanation

Main cause and required action

Function check operation in progress via
external communications

This display does not occur withordinary specifications.

Currently in SETUP MODE----

Automatic reference calibration (optional
function) being performed

This display does not occur withordinary specifications.

Warm-up in progress

If the calorimeter is restarted,
it enters 15-minute warm-up
state.

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9 Troubleshooting

9-5. CAUTION screen

9-5. CAUTION screen
Display
EnglishChineseJapanese

Main cause and required
action
Displayed before the LCD
screen and contacts are
unlatched.
When entering the SETUP
MODE, this screen isdisplayed before themeasurement is stopped and4 - 20 mA is fixed to thespecified output value.
This screen is displayed in the
SETUP MODE when a signal
output different from thespecified value is requested.

Display

Main cause and required action
When "Reference calibration" described in Section 6.2.6 is performed in
the SETUP MODE, this screen is displayed upon the detection of data
greatly different from the last result.
A sufficient amount of reference gas may not be supplied from GAS IN of
the OHC-800. Check the operations and procedures thoroughly forcorrectness, and select "OK."
If this screen is frequently displayed, a malfunction of the optical sensor
unit or sampling device is suspected.
When the settings are changed in the SETUP MODE, this screen isdisplayed upon a failure in writing the setting information to FRAM. If awrite failure occurs repetitiously or frequently, a malfunction of the main
controller is suspected.
When the settings are changed in the SETUP MODE, this screen isdisplayed upon a failure to supply the power required to write the setting
information to FRAM. Unless an abnormality is found in the power supply
to the OHC-800, a malfunction of the power terminal unit or main
controller is suspected.
This screen is displayed only under special work conditions such as
those in the manufacturing process of the OHC-800.

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9 Troubleshooting

9-6. Others

9-6. Others
Display

Main cause and required action
When you are prompted to enter a password when switching to the
SETUP MODE, entering an incorrect password causes the screen on theleft to be displayed.
Press the SET or ESC key to repeat the operation to enter the SETUP
MODE.

77 / 87

9 Troubleshooting

9-7. If not applicable to display

9-7. If not applicable to display
Display
The power cannot be
turned on.

Main cause

Required action

Power switch isturned off

Turn ON the power switch.

The fuse has blownout

Check the fuse, if it has blown out, replace it with the
rated fuse.

Abnormalities/momentary blackout of
power supply system

Check the power supply voltage.
Provide the rated voltage.
Take measures such as checking or adding the UPS,
power supply line filter and insulation transformer.

Internal connection
cable abnormalities(open circuit/not
connected/shortcircuit)Check for a condition of the internal cable pulls out/
clashed/broken/short circuit.
If there is an abnormality on the flat-cable, replacementof the main unit is required, please contact RIKEN
KEIKI.
If there is an abnormality on the cable connected withthe terminal, retry the wire connection.

External connection
cable abnormalities(open circuit/not
connected/shortcircuit)Check for a condition of the external cable pulls out/
clashed/broken/short circuit.
If there is an abnormality on the cable, replace thecable.

Nothing is displayed.

78 / 87

10 Product Specifications

10-1. Product specifications

10

Product Specifications
10-1. Product specifications
Specification
Model:
Measuring principle:

OHC-800
Opt-Sonic calculation through measurement of refractive index and soundspeed
Measuring gas:
See "Measuring gas specification sheet" attached.
Measuring targets:
Calorific value, density (specific gravity), and WOBBE index
Measuring range:
See "Measuring gas specification sheet" attached.
Measuring method:
Constant-flow-rate gas introduction using external sampling devices
Self-monitoring/diagnostic Status monitoring using four classification categories
function:
 FAILURE
 FUNCTION CHECK MAINTENANCE REQUIRED OUT OF SPECIFICATION
Display:
Full-dot LCD (with backlight)
Lamps
Green:
Lights up at power on.
Orange: Lights up in conjunction with Contact Output 1.
Red:
Lights up in conjunction with Contact Output 2.
Green:
Lights up in conjunction with Contact Output 3.
External Output 1:
4 - 20 mA DC (insulated, source current type) maximum load resistance of
300 Ω, minimum resolution under 0.01 mA
External Output 2:
RS-485 (MODBUS) communication function
External Output 3:
IrDA communication output (for maintenance)
Contact Output 1: *1
Activated if the FUNCTION CHECK or OUT OF SPECIFICATION condition ismet.*[No-voltage contact, contact capacity of 2 A, 30 VDC (resistance load)]
Contact Output 2: *1
Activated if the FAILURE condition is met.*[No-voltage contact, contact capacity of 2 A, 30 VDC (resistance load)]
Contact Output 3: *1
Activated if the MAINTENANCE REQUIRED condition is met.*[SSR contact, contact capacity of 20 W, 240 VAC (resistance load)]
How to operate:
Operation using a magnet control key(The calorimeter can be operated while maintaining the explosion-proof
performance.)
Power supply: *2
100 - 240 VAC ±10%, 50/60 Hz, max. 18 VA or 24 VDC ±10%, max. 5 W (Thesetting can be changed to either the AC or DC specifications.)
Protection class:Equivalent to IP66 or IP67
Ambient temperature:
Japan Ex spec. ：-20 to +57°C(at a constant condition)
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10 Product Specifications

10-2. Principle of this productIECEx / ATEX / China Ex spec. ：-20 to +60°C

Ambient humidity:
Measuring gas
temperature:
Outer dimensions:
Weight:Explosion-proof class

95%RH or less(Non-condensing)Same as ambient temperature
Approx. 286 (W) x 453 (H) x 150 (D) mm
Approx. 23 kg
Japan Ex
IECEx
ATEX
China Ex：Ex d ⅡB+H2 T4：Ex db ⅡB+H2 T4 Gb：Ⅱ2 G Ex db ⅡB+H2 T4 Gb：Ex d ⅡB+H2 T4 Gb*1 The operating conditions of contacts can be changed.
*2 For CE marking specifications, DC specitications only.
* Specifications subject to changes without notice.

10-2. Principle of this product10-2-1. Opt-Sonic calculation (calorific value)
Figure 1 is a graph that shows the correlation between the calorific value of pure gases and sound speed.
The straight line drawn in this figure represents the function QSonic that connects the points of paraffinichydrocarbon gases.
Figure 2 is a graph that shows the correlation between the calorific value of pure gases and refractive index.
The straight line drawn in this figure represents the function QOpt that connects the points of paraffinichydrocarbon gases.

Figure 1: Correlation between calorific value andsound speed

Figure 2: Correlation between calorific value andrefractive index

If the gas to be measured consists only of paraffinic hydrocarbon gases, an accurate calorific value can beobtained by measuring sound speed and refractive index and substituting them into the functions QSonic
and QOpt.
However, if the gas to be measured includes components with sound speed and refractive index that are
not on the straight lines drawn by the functions QSonic and QOpt, respectively, i.e., N2, O2, CO2, CO etc.,
these components act as interference gases that generate errors.
The correlation between the true calorific value of the measuring gas Q and the functions QSonic and QOpt
can be expressed by the following formulas (1) and (2).

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10 Product Specifications

10-2. Principle of this productQ  QOpt   k i  xi

(1)

Q  QSonic   k 'i xi(2)where xi represents the volume fraction of interference gas component i, and ki and k'i represent the error
coefficients caused by interference gas component i.
The error coefficients ki and k'i represent the "distances" in a vertical axis direction from the component i tothe straight lines drawn by the functions QSonic and QOpt in the graphs shown in Figures 1 and 2.
RIKEN KEIKI has discovered a correlation in which the ratio of ki to k'i is approximately constant,regardless of the types of interference gases.

k 'i    k i(3)Using the relational formula (3), the formula (2) can be written as follows:

Q  QSonic     ki  xi

(4)

The formulas (1) and (4) can be used to derive the relational formula of the Opt-Sonic calculation for
obtaining calorific value.

Q  QOpt 

QOpt  QSonic

(5)

1

Figure 3 shows the correlation between the Opt-Sonic calculation and calorific value.
Not only the paraffinic hydrocarbon gases but also the components N2, O2, CO2, and CO are on one
straight line, demonstrating that the influences of interference gases have been effectively removed.

Figure 3: Correlation between Opt-Sonic calculation and calorific value

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10 Product Specifications

10-2. Principle of this product10-2-2. Opt-Sonic calculation (specific gravity)
Figure 4 is a graph that shows the correlation between the specific gravity of pure gases and sound speed.
The straight line drawn in this figure represents the function dSonic that connects the points of paraffinichydrocarbon gases.
Figure 5 is a graph that shows the correlation between the specific gravity of pure gases and refractive
index. The straight line drawn in this figure represents the function dOpt that connects the points ofparaffinic hydrocarbon gases.

Figure 4: Correlation between specific gravity andsound speed

Figure 5: Correlation between specific gravity andrefractive index

If the gas to be measured consists only of paraffinic hydrocarbon gases, an accurate specific gravity can beobtained by measuring sound speed and refractive index and substituting them into the functions dSonic
and dOpt.
However, if the gas to be measured includes components with sound speed and refractive index that are
not on the straight lines drawn by the functions dSonic and dOpt, respectively, i.e., N2, O2, CO2, CO etc.,
these components act as interference gases that generate errors.
The correlation between the true specific gravity of the measuring gas d and the functions dSonic and dOpt
can be expressed by the following formulas (6) and (7).

d  d Opt   k i  xi

(6)d  d Sonic   k 'i xi(7)where xi represents the volume fraction of interference gas component i, and ki and k'i represent the error
coefficients caused by interference gas component i.
The error coefficients ki and k'i represent the "distances" in a vertical axis direction from the component i tothe straight lines drawn by the functions dSonic and dOpt in the graphs shown in Figures 4 and 5.
RIKEN KEIKI has discovered a correlation in which the ratio of ki to k'i is approximately constant,regardless of the types of interference gases.

  k 'i  k i(8)Using the relational formula (8), the formula (6) can be written as follows:d  d Opt     k i  xi

(9)82 / 87

10 Product Specifications

10-2. Principle of this product

The formulas (7) and (9) can be used to derive the relational formula of the Opt-Sonic calculation for
obtaining specific gravity.

d  d Sonic 

d Sonic  d Opt

(10)

1 

Figure 6 shows the correlation between the Opt-Sonic calculation and specific gravity.
Not only the paraffinic hydrocarbon gases but also the components N2, O2, CO2, and CO are on one
straight line, demonstrating that the influences of interference gases have been effectively removed.

Figure 6: Correlation between Opt-Sonic calculation and specific gravity

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10 Product Specifications

10-2. Principle of this product10-2-3. Principle of optical sensor
Plane-parallel mirror

L/2Interference
fringes

Prism

GAS chamber
Measuring gas

cReference gasbMeasuring gasaMirror
LED light source

Lens

Interference fringes suchas the ones shown above
are formed here.

Lens

A schematic diagram of the interferometer used in the optical sensor is shown above. This
interferometer forms "interference fringes" that move in proportion to the "differences of refractive
index" between the measuring and reference gases.
The movement distance of interference fringes Δθ can be expressed as the following formula: 

2LnGAS  n REF L:Chamber length
nGAS: Refractive index of measuring gas
nREF: Refractive index of reference gas
λ:Light source wavelength
The light source wavelength and chamber length are physically quite stable. Therefore, the refractive index
of measuring gas nGAS can be accurately obtained by measuring the movement distance of interference
fringes.

84 / 87

10 Product Specifications

10-2. Principle of this product10-2-4. Principle of sonic sensor
Sound sourceSoundreceiverMeasuring gas inlet

Measuring gas outlet

A schematic diagram of the sonic sensor is shown above. This sensor emits a sound from the soundsource into a tube in which a measuring gas flows and then measures the time τ in which the soundtravels through the measuring gas and arrives at the sound receiver.
The speed of sound that travels through the measuring gas vGAS can be expressed as the following
formula:vGAS L

L: Distance from the sound wave source to the sound receiver
τ: Time in which a sound from the sound source arrives at the sound receiver
The distance from the sound source to the sound receiver L is physically quite stable. Therefore, the speed
at which a sound travels through the measuring gas vGAS can be accurately obtained by measuring thesound travel time τ.

85 / 87

11 Definition of Terms

11-1. Definition of terms used in operating manual

11

Definition of Terms
11-1. Definition of terms used in operating manual
Measuring gas

Gas used to measure calorific value, density, and WOBBE index on this product.

Refractive index

One of the indexes for how the light travels through a substance. This value isobtained by dividing the speed of light that travels through a vacuum by the speedof light that travels through a substance.
Gas used on an optical sensor unit as a reference for measuring the refractive
index of a measuring gas. The gas type varies depending on the productspecifications.

Reference gas

Reference gas
calibration (REF
CAL.)

Operation for adjusting the reading when measuring the reference gas
concentration.

Opt-Sonic
calculation

This proprietary technology developed by RIKEN KEIKI in 2007 and 2010 refers to
calculating the "calorific value" and "density" of a fuel gas with high accuracy bymeasuring the speeds of "light" and "sound" that travel through the fuel gas andeliminating the influence of interference gases such as N2, CO2, CO, and O2
through calculation.
Coefficient that is set to eliminate the influence of interference gases whencalculating "calorific value" in Opt-Sonic calculation.
This value is determined by the major fluctuating components of interference
gases in the fuel gas.
Coefficient that is set to eliminate the influence of interference gases whencalculating "density" in Opt-Sonic calculation.
This value is determined by the major fluctuating components of interference
gases in the fuel gas.

Calculation Factor αCalculation Factor β

86 / 87

11 Definition of Terms

11-2. Definition of terms used in "Measuring gas specification sheet"

11-2. Definition of terms used in "Measuring gas
specification sheet"
Instrument air
MJ/m3
Gross
(HHV, SCV)

Net
(LHV, ICV)Standard
temperatureStandard pressure
kg/m3
Specific gravity[AIR = 1]

WOBBE index

Dry, clean air. Use Classes 1.1.1 to 1.6.2 stipulated in JIS B8392-1:2003 (ISO8573-1:2001). In cold climates, use Classes 1.1.1 to 1.3.2.
Calorific value per cubic meter expressed in SI units.
All of these terms are synonymous, which are abbreviations for Gross calorificvalue (Gross), Higher Heating Value (HHV) and Superior Calorific Value (SCV).
This calorific value includes "latent heat" obtained when water vapor generated
during combustion is compressed.
All of these terms are synonymous, which are abbreviations for Net calorific value(Net), Lower Heating Value (LHV) and Inferior Calorific Value (ICV).
This calorific value does not include "latent heat" obtained when water vapor
generated during combustion is compressed.
Temperature of a gas to be used as a reference for measuring and displaying
calorific value and density in units per unit volume.
Pressure of a gas to be used as a reference for measuring and displaying calorificvalue and density in units per unit volume.
Mass per cubic meter expressed in SI units.
Value obtained by dividing the density of a certain substance by that of areference substance.
To obtain the specific gravity of a gas, it is a common practice to use air as thereference. The OHC-800 also derives a specific gravity using air as the reference.
The WOBBE index (W.I.) is one of the combustion quality indexes. This value isobtained by dividing a calorific value by the square root of a specific gravity.
This value is in proportion to the calorific value released per unit of time when agas is supplied under a certain pressure to a nozzle with a certain orifice.

87 / 87