PT2E-17412

Combustible Gas Detector HeadGD-D58・AC
GD-D58・DC(TYPE GP)(TYPE NC)

Operating Manual

Operating Precautions
This detector head is a gas detector that detects combustible gases in the air and triggers a gas alarm.
The gas detector is a safety unit, not an analyzer or densitometer which performs quantitative/qualitative
analysis/measurement for gases.
Please fully understand the following points before using it, so that it can be used properly.
1.

This detector head may be interfered by gases and vapors other than the gas to be detected.
Please note that the alarm may be triggered by interference. In addition, it may be fluctuated byenvironmental (temperature, humidity, etc.) changes in the installation site.

2.

The alarm must be set within a range where the performance of the detector head can be ensured.
In facilities compliant with the High Pressure Gas Safety Act, an alarm setting below our standard
alarm setpoint may trigger a false alarm.

3.

This is a safety unit, not a control unit.
The alarm contact output of the detector head must be used for an external alarm lamp/buzzer, while
the alarm signal output must be used for an indicator or external recorder.
If these outputs are used to control other units, we shall not be responsible for any malfunctions.

4.

The gas sensing part of the gas sensor installed in this detector head is made of metal porous sinteredalloy permeated with an oxidation catalyst.
If silicon or sulfide compounds are accumulated on the surface of porous sintered alloy, the area of thegas sensing part becomes smaller, which may results in serious deterioration of its sensitivity.
For safety reasons, do not use the detector head under the presence of silicon or sulfide compounds
even though their amount is very small.

5.

For maintenance of the detector head, it must go through a regular maintenance, including
replacement and adjustment of the regular replacement parts as specified in the operating manual. In
addition, because this is a safety unit, it is recommended that a regular maintenance and a gas
calibration are performed every six months in accordance with the regulations.

-2-<Contents>

1. Outline of the Product ........................................................................................................ 4
1-1. Preface ............................................................................................................................ 4
1-2. Purpose of use ................................................................................................................ 4
1-3. Definition of DANGER, WARNING, CAUTION, and NOTE ............................................. 4
1-4. Method of confirmation for Standards and Explosion proof specification ........................ 5
2. Important Notices on Safety............................................................................................... 6
2-1. Danger cases .................................................................................................................. 6
2-2. Warning cases ................................................................................................................. 7
2-3. Precautions ..................................................................................................................... 8
2-4. Safety Information ........................................................................................................... 9
3. Product Components ......................................................................................................... 13
3-1. Main unit and standard accessories ................................................................................ 13
3-2. Names and functions for each part.................................................................................. 15
3-3. Block diagram.................................................................................................................. 18
4. How to Use ........................................................................................................................ 20
4-1. Before using the detector head ....................................................................................... 20
4-2. Precautions for installation points .................................................................................... 20
4-3. Precautions for system designing.................................................................................... 21
4-4. How to install ................................................................................................................... 23
4-5. How to wire...................................................................................................................... 25
4-6. How to tube ..................................................................................................................... 32
5. How to Operate.................................................................................................................. 33
5-1. Preparation for start-up ................................................................................................... 33
5-2. Basic operating procedures ............................................................................................. 33
5-3. How to start the detector head ........................................................................................ 34
5-4. How to detect .................................................................................................................. 35
5-5. How to exit....................................................................................................................... 35
6.

Alarm Activation ................................................................................................................. 36

7. Maintenance ...................................................................................................................... 37
7-1. Maintenance intervals and items ..................................................................................... 37
7-2. Parts replacement ........................................................................................................... 39
8. Storage, Relocation and Disposal...................................................................................... 40
8-1. Procedures to store the detector head or leave it for a long time .................................... 40
8-2. Procedures to relocate the detector head or use it again ................................................ 40
8-3. Disposal of products ........................................................................................................ 40
9. Troubleshooting ................................................................................................................. 41
10. Product Specifications ........................................................................................................ 43
10-1. List of specifications ...................................................................................................... 43
10-2. Detection principle ......................................................................................................... 48
11. Definition of Terms .............................................................................................................. 50-3-

GD-D58 Series1 Outline of the Product1-1. Preface

1

Outline of the Product1-1. Preface
Thank you for choosing our fixed-type combustible gas detector head GD-D58 series. Please check thatthe model number of the product you purchased is included in the specifications on this manual.
This manual explains how to use the detector head and its specifications. It contains information required
for using the detector head 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 detector head.
Note that the detector head cannot be used by itself. Be sure to use it in combination with the dedicatedindicator/alarm unit. Read also the operating manual of the indicator/alarm unit.

1-2. Purpose of use
 This detector head is a fixed type gas detector head which detects combustible gases.
 Use this detector head in combination with an indicator/alarm unit that indicates a gas concentrationand triggers an alarm.
The detector head detects combustible gases and outputs voltages according to gas concentrations.
The indicator/alarm unit both indicates a gas concentration and, if a preset concentration level isexceeded, triggers an alarm.
 The detector head is a safety unit, not an analyzer or densitometer which performs
quantitative/qualitative analysis/measurement for gases. Please fully understand the features of thedetector head before using it, so that it can be used properly.
 The detector head draws air with the built-in pump and detects abnormalities in the air caused bypresence of gases or other reasons (leak) with the built-in gas sensor.
 The detector head has a built-in low flow rate detection function and can trigger a fault alarm when theflow rate inside the tubing drops below a fixed rate.
 The detector head has two types of power supply specifications.
GD-D58·ACGD-D58·DC

AC specification
DC power specification

100 - 110 VAC
24 VDC

1-3. Definition of DANGER, WARNING, CAUTION, andNOTE
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.

GD-D58 Series-4-2 Important Notices on Safety

2-4. Safety Information

2-4. Safety Information
Necessary information for explosion proof construction of Model GD-D58・AC／GD-D58・DC.
This product is a diffusion type gas detector which is basically installing fixed place.
<ATEX/UKEX Specifications>Technical Data
(Protection Method)(Certificate numbers)(Group)(Category)(Type of Protection and Marking code)(Equipment Protection Level)(Ambient Temperature)(Electrical Data)
Supply voltage :Output signal :Sensor power supply : Gas sensor
Flow sensor(Applicable Standard)

Flameproof enclosure “d”
DNV 21 ATEX 63457X
DNV 22 UKEX 25926X
II
2G
Ex db h ⅡB+H2 T4
Gb-20C to +53C
24 Vdc(Typ.)DC3.0V 430mA
DC5.0V 200mA or DC3.0V 430mA
DC2.0V 170mA
EN IEC 60079-0 : 2018，EN 60079-1: 2014
BS EN IEC60079-0:2018, BS EN 60079-1:2014

Specific conditions of “X”-mark:Fasteners used for enclosure arefrom stainless steel property class A2-70.
Cable gland may not provide sufficient clamping. User shall provide additional clamping of the cable toensure that pulling and twisting isnot transmitted to the terminations.
Regarding ATEX specification, the measuring function according to Annex II paragraph 1.5.5 of the
Directive is not covered by this EU-type examination.
It shall comply with the requirements from the relevant European harmonized standards which provide
guidance on the performance of gas detection equipment and safety devices.
The measuring function according to schedule 1, paragraph 24 of the Regulation is not covered in this UKtype examination. It shall comply with the requirements from the relevant UK Designated Standards which
provide guidance on the performance of gas detection equipment.
The flameproof joints not intended to be repaired.
Enclosure made of Aluminum – Avoid impact or Friction in the equipment.

-9-

GD-D58 Series4 How to Use

4-3. Precautions for system designing

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, "lightning" will cause problems. Because lightning acts as alarge emission source while cables act as a receiving antenna, devices connected to the cables may bedamaged.
Lightning cannot be prevented. Cables installed in a metal conduit or under the ground cannot becompletely protected from inductive lightning surge caused by lightning. Although complete elimination ofdisasters 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.
 Provide protection by a lightning arrester (cable arrester).
Protection against(Although inductive lightning surge can be transmitted through the cable, it islightning
prevented by installing a lightning arrester before the field devices and central
processing equipment. For information on how to use a lightning arrester,
please contact the manufacturer.）
In addition to lightning, there are more sources of surge noise. To protect units from
Groundingthese noise sources, the units must be grounded.
* The lightning arrester has a circuit to remove a surge voltage which damages field devices, so thatsignals may be attenuated. Before installing a lightning arrester, verify that it works properly.

GD-D58 Series- 22 -

5 How to Operate

5-1. Preparation for start-up

5

How to Operate
5-1. Preparation for start-up
Before supplying power, read and understand the following precautions. Ignoring these precautions may
cause an electric shock or damage the detector head.






Check that the detector head is installed properly.
Check that the detector head is connected to a grounding circuit.
Check that the wiring is connected to external device properly.
Check that the tubes are installed properly.
Check that the power supply voltage is compliant with the power supply specification and does notexceed the rating.

5-2. Basic operating procedures
Normally, the detection mode is activated after the power is turned on.
The detector head isrestarted after
recovering from fault.

<<Detection Mode>>
Lamp onLamp off
Lamp blinking<<Fault Status>>* Example of display: E-5 Low Flow Rate Alarm- 33 -

GD-D58 Series6 Alarm Activation

5-5. How to exit

6

Alarm Activation
A fault alarm is triggered when the detector head detects abnormalities. After a fault alarm is triggered, thefault lamp (yellow) lights up and an error message is displayed on the LED. Determine the causes and takeappropriate actions.
After the detector head is successfully returned from the fault, it restarts with the process normally
performed right after it is turned on (initial clear).
If the detector head has problems and is repeatedly malfunctioning, contact RIKEN KEIKI immediately.

<Low Flow Rate Abnormal Operations>This alarm is triggered when the output value of the low flow sensor drops below the alarm setpoint.
The alarm is auto-reset when the flow rate exceeds a certain level.

Flow sensor
output value

Alarm setpoint value

0
Time

FAULT lamp lights up
Alarm delay time (15 seconds)

NOTE A low flow rate abnormality can be a cause of fault alarm.
For information on malfunctions (error messages), see "9. Troubleshooting".
 When a fault alarm is triggered, the indicator/alarm unit reports a sensor abnormality or fault alarm*.
* The display of an alarm depends on the indicator/alarm unit. For details, see the operating manualof the indicator/alarm unit.

GD-D58 Series- 36 -

7 Maintenance7-1. Maintenance intervals and items

7

MaintenanceThe detector head is an important instrument for the purpose of safety.
To maintain the performance of the detector head and improve the reliability of safety, perform a regular
maintenance.
Continuing to use the detector head without performing a maintenance will compromise the sensitivity of
the gas sensor, thus resulting in inaccurate detection.

7-1. Maintenance intervals and items
 Daily maintenance:
 Monthly maintenance: Regular maintenance:

Maintenance item

Perform maintenance before beginning to work.
Perform alarm test once a month.
Perform maintenance once or more every six months to maintain theperformance as a safety unit.
Maintenance content

Daily
maintenance

Monthly
maintenanceRegularmaintenancePower lamp check

Check that the power lamp lights up.







Status display check

Check that the status display is "run" andthat the fault lamp is off.







Flow rate check

Check that the float of the dust removal
filter with flow monitor is visible.







Gas concentration
display*

Check that the gas to be detected does
not remain near the detector head(sampling point) and that the reading isnormal.



Alarm test*

Check the alarm circuit by using the alarm
test function.

-





Span adjustment*

Perform the sensitivity calibration by using
the calibration gas.

-

-



Gas alarm check*

Check the gas alarm by using thecalibration gas.

-

-



Flow sensor check

Check the flow sensor by using the testpump.
* Check and adjust at the indicator/alarm unit side. For details, see the operating manual of the indicator/alarm unit.

- 37 -

GD-D58 Series

7 Maintenance7-1. Maintenance intervals and items<About Maintenance Services> We provide services on regular maintenance including span adjustment, other adjustments andmaintenance.
To make the calibration gas, dedicated tools, such as a gas cylinder of the specified concentration andgas sampling bag must be used.
Our qualified service engineers have expertise and knowledge on the dedicated tools used for services,along with other products. To maintain the safety operation of the detector head, please use ourmaintenance service.
 The followings are typical maintenance services. For more information, please contact RIKEN KEIKI.
Main services
Power supply
check
Status display
check
Concentration
display check*
Flow rate check
Filter check:::

Alarm test*:

Span adjustment*
Gas alarm check*::

Cleaning andrepair of device(visual diagnosis)
Device operation
check
Replacement ofconsumable parts::

Checks the power supply voltage.
Verifies that the power lamp lights up.
Checks that the status display is "run" and that the fault lamp is off.

:

Verifies that the concentration display value is zero by using the zero gas.
Performs the zero adjustment if the display value is incorrect.
Checks the flow rate by using an external flow meter to check for abnormalities.
Checks the dust filter for dust or clogging.
Replaces a dirty or clogged dust filter.
Inspects the alarm circuit by using the alarm test function.
 Checks the alarm lamps. (Checks activation.) Checks the external alarm. (Checks the activation of the external alarm, such as a buzzer.)
Performs the span adjustment by using the calibration gas.
Checks the gas alarm by using the calibration gas.
 Checks the alarm. (Checks the alarm activation when the alarm setpoint is reached) Checks the delay time. (Checks time to delay until the alarm is triggered.) Checks the alarm lamps. (Checks activation.) Checks the external alarm. (Checks the activation of external alarms, such as a buzzer and reset
signal.)Checks dust or damage on surface, cover, or internal parts of the detector head, cleans and repairs suchparts of the device.
Replaces parts which are cracked or damaged.
Uses the keys to check the operation of functions and parameters.

:

Replaces consumable parts, such as a sensor, filter and pump.

* Inspect and adjust the indicator/alarm unit.

GD-D58 Series- 38 -

7 Maintenance7-2. Parts replacement

7-2. Parts replacement<Gas Sensor, Flow Sensor, and Pump Replacement>
Our service engineers need to replace and calibrate these parts. Please contact RIKEN KEIKI.

NOTE
The gas calibration using the standard gas is required after the gas sensor is replaced. Adjustment isrequired after the flow sensor or pump is replaced. Please contact RIKEN KEIKI.
As a guide, replace the sensors of the detector head with new ones every one to three years.

<Replacement of Regular Replacement Parts>
List of recommended regular replacement parts
Name

Maintenanceintervals

Replacement
intervals (year)

Quantity(pieces/unit)

Remarks

AC/DC converter

6 months

3 - 6 years

1※

Flow sensor

6 months

2 years

1

※

Tubes

6 months

3 - 8 years

1※

Pump unit

6 months

1 - 2 years

1※

Chamber assembly

6 months

3 - 8 years

1※

Sensor cap assembly

6 months

3 - 8 years

1※※After the part is replaced, the operation must be checked by a qualified service engineer.
For the stable operation of the detector and safety, ask a qualified service engineer to take care of
replacement of the parts whose operation must be checked. Please contact our sales department.

NOTE
The above replacement intervals are recommendation only. The intervals may change depending on theconditions such as the operating environment. These intervals do not mean the warranty periods either.
The result of the regular maintenance may determine when to replace the parts.

- 39 -

GD-D58 Series

9 Troubleshooting

9

Troubleshooting
The Troubleshooting does not explain the causes of all the malfunctions which occur on the detector head.
This simply helps to find the causes of malfunctions which frequently occur. If the detector head shows asymptom which is not explained in this manual, or still has malfunctions even though remedial actions aretaken, please contact RIKEN KEIKI.

<Abnormalities on Unit>
Symptom/Display

The power cannot
be turned on.

Abnormaloperations

FAULT

―

―

Low flow rateabnormality
E-5

Systemabnormalities
E-9

CausesActions

The wiring is not correct.

Connect the wiring properly.

The terminal plate isremoved.

Connect the terminal plate properly.

Abnormalities/momentary
blackout of power supply
systemProvide the rated voltage.
Take measures such as checking or adding the UPS,
power supply line filter and insulation transformer.

Cable abnormalities(open circuit/not
connected/short circuit)

Check the wiring of detector head and related devices
around it.

Disturbances by sudden
surge noise,etc.

Turn off and restart the detector head.
If such a symptom is observed frequently, takeappropriate measures to eliminate the noise.

The flow rate is low.

The possible causes are deterioration or clogging of thepump or clogging of the tube. Check the flow rate.

Faults of the flow sensor

Replace the sensor with a new one.

Abnormalities of ROM,
RAM, or EEPROM insideof the detector head

Please contact RIKEN KEIKI.

- 41 -

GD-D58 Series9 Troubleshooting<Abnormalities of Readings>* Perform troubleshooting on it as well as the indicator/alarm unit. For details, see the operating manual of
the indicator/alarm unit.
Symptoms

CausesDrifting of sensor
outputPresence ofinterference gas

The reading rises (drops)
and it remains so.
Slow leakA gas alarm is triggered
despite of no gas leak andno other abnormalities atthe detection point.

Slow response
Span adjustment
impossible

GD-D58 Series

Actions
Perform the zero adjustment.
Disturbances by interference gases, such as solvents, cannot
be eliminated completely. For information on actions such, asremoval filter, please contact RIKEN KEIKI.
A very small amount of the gas to be detected may beleaking (slow leak). Because ignoring it may cause dangers,
take a remedial measure, i.e., taking actions the same as
those for the gas alarm.

Environmental
changes

Perform the zero adjustment.

Presence ofinterference gas

Disturbances by interference gases, such as solvents, cannot
be eliminated completely. For information on actions such as
removal of filter, please contact RIKEN KEIKI.

Disturbance by noise

Turn off and restart the detector head.
If such a symptom is observed frequently, take appropriate
measures to eliminate the noise.

Sudden change in theenvironment

When the environment (temperature, etc.) changes suddenly,
the detector head cannot adjust to it and is affected by it. In
some cases, the detector head triggers an indication alarm.
Because the detector head cannot be used under sudden
and frequent environmental changes, you must take any
preventive actions to eliminate them.

Sensor sensitivity
deterioration
Improper calibration
gas concentration
Sensor sensitivity
deterioration

Replace the sensor with a new one.
Use the proper calibration gas.
Replace the sensor with a new one.

- 42 -

10 Product Specifications

10-1. List of specifications

10

Product Specifications
10-1. List of specifications[GD-D58•DC(TYPE GP)/GD-D58•DC(TYPE NC)] ＜ATEX/UKEX Specifications＞
Model
Type
Detection principle
Detection gas
Display
Detection method
Flow rate
Power display
Fault alarm/self
diagnosis
Fault alarm display
Fault alarm pattern
Transmission system
Pump power cable
Power cable laying
distance
Transmission cable
Power supply
Power consumption
Cable connecting port

GD-D58･DC
TYPE GPTYPE NC
Catalytic combustion typeNew ceramic typeCombustible gas
Seven-segment LED (four-digit)
Sample-drawing
1.0 L/min or more (at maximum suction pressure of 5.0 kPa <gauge pressure>)
POWER lamp on (green)
System abnormality/low flow rate
FAULT lamp on (yellow)/detail display
Non latching (Auto-reset)
Sensor direct output
CVV, etc. (1.25mm2 or 2.0mm2) - 2-coreLess than 375m in case of CVV 1.25mm2
Less than 550m in case of CVV 2.0mm2
CVVS, etc. (1.25mm2 or 2.0mm2) - 4-core or 6-core(in common with power cable)
24 VDC 10%
Maximum 8.6 W
Pressure proof packing gland<G3/4>(Compatible cables φ9.0 – φ16.0mm in outer
diameter)Tube connecting port

Rc1/8 (O.D8-1t half-union for Cu tube <Bs> supplied or half-union for SUS tube
<SUS>)
Operating temperature-20 - +53ºC (at a constant condition)
Operating humidity
Below 95% RH (Non-condensing)
Structure
Wall mounting type (2B<50A> pipe installation supported)
Explosion-proof structure Flame-proof enclosures
Explosion-proof class
Ⅱ 2G Ex db h ⅡB+H2 T4 Gb
IP ratingDimension
WeightOuter color

Equivalent to IP67
Approx. 197 (W) x 292 (H) x 140 (D) mm (projection portions excluded)
Approx. 5.8 kg
Munsell 7.5BG5/2* Specifications subject to changes without notice.

- 43 -

GD-D58 Series

10 Product Specifications

10-1. List of specifications[GD-D58•AC(TYPE GP)/GD-D58•AC(TYPE NC)] ＜Taiwan Ex(TS) Specifications＞
Model
Type
Detection principle
Detection gas
Display
Detection method
Flow rate
Power display
Fault alarm/self
diagnosis
Fault alarm display
Fault alarm pattern
Transmission system
Pump power cable
Power cable laying
distance
Transmission cable
Power supply
Power consumption
Cable connecting port

GD-D58･AC
TYPE GPTYPE NC
Catalytic combustion typeNew ceramic typeCombustible gas
Seven-segment LED (four-digit)
Sample-drawing
1.5 L/min or more (at maximum suction pressure of 5.3 kPa <gauge pressure>)
POWER lamp on (green)
System abnormality/low flow rate
FAULT lamp on (yellow)/detail display
Non latching (Auto-reset)
Sensor direct output
CVV, etc. (1.25mm2 or 2.0mm2) - 2-core or 3-coreLess than 1.25km in case of CVV 1.25mm2
Less than 2.0km in case of CVV 2.0mm2
CVVS, etc. (1.25mm2 or 2.0mm2) - 4-core or 6-core(in common with power cable)
100 - 110 VAC ±10%, 50/60 Hz
Maximum 13 VA
Pressure proof packing gland<G3/4>(Compatible cables φ9.0 - φ16.0mm in outer
diameter)Tube connecting port

Rc1/8 (O.D8-1t half-union for Cu tube <Bs> supplied or half-union for SUS tube
<SUS>)
Initial clear
Approx.25sec
Operating temperature-20 - +50ºC (at a constant condition)
Operating humidity
Below 95% RH (Non-condensing)
Structure
Wall mounting type (2B<50A> pipe installation supported)
Explosion-proof structure Flame-proof enclosures
Explosion-proof class
Ex d ⅡB+H2 T4 Gb
IP ratingDimension
WeightOuter color

Equivalent to IP67
Approx. 197 (W) x 292 (H) x 140 (D) mm (projection portions excluded)
Approx. 5.8 kg
Munsell 7.5BG5/2* Specifications subject to changes without notice.

GD-D58 Series- 44 -

10 Product Specifications

10-1. List of specifications[GD-D58•DC(TYPE GP)/GD-D58•DC(TYPE NC)] ＜Taiwan Ex(TS) Specifications＞
Model
Type
Detection principle
Detection gas
Display
Detection method
Flow rate
Power display
Fault alarm/self
diagnosis
Fault alarm display
Fault alarm pattern
Transmission system
Pump power cable
Power cable laying
distance
Transmission cable
Power supply
Power consumption
Cable connecting port

GD-D58･DC
TYPE GPTYPE NC
Catalytic combustion typeNew ceramic typeCombustible gas
Seven-segment LED (four-digit)
Sample-drawing
1.0 L/min or more (at maximum suction pressure of 5.0 kPa <gauge pressure>)
POWER lamp on (green)
System abnormality/low flow rate
FAULT lamp on (yellow)/detail display
Non latching (Auto-reset)
Sensor direct output
CVV, etc. (1.25mm2 or 2.0mm2) - 2-coreLess than 375m in case of CVV 1.25mm2
Less than 550m in case of CVV 2.0mm2
CVVS, etc. (1.25mm2 or 2.0mm2) - 4-core or 6-core(in common with power cable)
24 VDC 10%
Maximum 8.6 W
Pressure proof packing gland<G3/4>(Compatible cables φ9.0 - φ16.0mm in outer
diameter)Tube connecting port

Rc1/8 (O.D8-1t half-union for Cu tube <Bs> supplied or half-union for SUS tube
<SUS>)
Operating temperature-20 - +53ºC (at a constant condition)
Operating humidity
Below 95% RH (Non-condensing)
Structure
Wall mounting type (2B<50A> pipe installation supported)
Explosion-proof structure Flame-proof enclosures
Explosion-proof class
Ex d ⅡB+H2 T4 Gb
IP ratingDimension
WeightOuter color

Equivalent to IP67
Approx. 197 (W) x 292 (H) x 140 (D) mm (projection portions excluded)
Approx. 5.8 kg
Munsell 7.5BG5/2* Specifications subject to changes without notice.

- 45 -

GD-D58 Series

10 Product Specifications

10-1. List of specifications[GD-D58•AC(TYPE GP)/GD-D58•AC(TYPE NC)] ＜Japan Ex Specifications＞
Model
Type
Detection principle
Detection principle
Detection gas
Display
Detection method
Flow rate
Power display
Fault alarm/self
diagnosis
Fault alarm display
Fault alarm pattern
Transmission system
Pump power cable
Power cable laying
distance
Transmission cable
Power supply
Power consumption
Cable connecting port
Tube connecting port

GD-D58･AC
TYPE GPTYPE NC
Catalytic combustion typeNew ceramic type
Catalytic combustion typeCombustible gas
Seven-segment LED (four-digit)
Sample-drawing
1.5 L/min or more (at maximum suction pressure of 5.3 kPa <gauge pressure>)
POWER lamp on (green)
System abnormality/low flow rate
FAULT lamp on (yellow)/detail display
Non latching (Auto-reset)
Sensor direct output
CVV, etc. (1.25mm2 or 2.0mm2) - 2-core or 3-coreLess than 1.25km in case of CVV 1.25mm2
Less than 2.0km in case of CVV 2.0mm2
CVVS, etc. (1.25mm2 or 2.0mm2) - 4-core or 6-core(in common with power cable)
100 - 110 VAC ±10%, 50/60 Hz
Maximum 13 VA
Pressure proof packing gland<G3/4>(Compatible cables φ9.0mm - in outer diameter)

Rc1/8 (O.D8-1t half-union for Cu tube <Bs> supplied or half-union for SUS tube
<SUS>)
Operating temperature-20 - +50ºC (at a constant condition)
Operating humidity
Below 95% RH (Non-condensing)
Structure
Wall mounting type (2B<50A> pipe installation supported)
Explosion-proof structure Flame-proof enclosures
Explosion-proof class
Ex d ⅡB+H2 T4
IP ratingDimension
WeightOuter color

Equivalent to IP67
Approx. 197 (W) x 292 (H) x 140 (D) mm (projection portions excluded)
Approx. 5.8 kg
Munsell 7.5BG5/2* Specifications subject to changes without notice.

GD-D58 Series- 46 -

10 Product Specifications

10-1. List of specifications[GD-D58•DC(TYPE GP)/GD-D58•DC(TYPE NC)] ＜Japan Ex Specifications＞
Model
Type
Detection principle
Detection principle
Detection gas
Detection method
Flow rate
Power display
Fault alarm/self
diagnosis
Fault alarm display
Fault alarm pattern
Transmission system
Pump power cable
Power cable laying
distance
Transmission cable
Power supply
Power consumption
Cable connecting port
Tube connecting port

GD-D58･DC
TYPE GPTYPE NC
Catalytic combustion typeNew ceramic type
Catalytic combustion typeCombustible gas
Sample-drawing
1.0 L/min or more (at maximum suction pressure of 5.0 kPa <gauge pressure>)
POWER lamp on (green)
System abnormality/low flow rate
FAULT lamp on (yellow)/detail display
Non latching (Auto-reset)
Sensor direct output
CVV, etc. (1.25mm2 or 2.0mm2) - 2-coreLess than 375m in case of CVV 1.25mm2
Less than 550m in case of CVV 2.0mm2
CVVS, etc. (1.25mm2 or 2.0mm2) - 4-core or 6-core(in common with power cable)
24 VDC 10%
Maximum 8.6 W
Pressure proof packing gland<G3/4>(Compatible cables φ9.0mm - in outer diameter)

Rc1/8 (O.D8-1t half-union for Cu tube <Bs> supplied or half-union for SUS tube
<SUS>)
Operating temperature-20 - +53ºC (at a constant condition)
Operating humidity
Below 95% RH (Non-condensing)
Structure
Wall mounting type (2B<50A> pipe installation supported)
Explosion-proof structure Flame-proof enclosures
Explosion-proof class
Ex d ⅡB+H2 T4
IP ratingDimension
WeightOuter color

Equivalent to IP67
Approx. 197 (W) x 292 (H) x 140 (D) mm (projection portions excluded)
Approx. 5.8 kg
Munsell 7.5BG5/2* Specifications subject to changes without notice.

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GD-D58 Series

10 Product Specifications

10-2. Detection principle

10-2. Detection principle[Catalytic Combustion Type]
When a combustible gas burns on the surface of an oxidation catalyst, the catalytic combustion typesensor considers resultant combustion heat as temperature and resistance changes in the platinum wirecoil, and measures their gas concentrations.
This sensor detects any combustible gases. The detection range is from zero to the lower explosive limit.
When a high-concentrated gas over the lower explosive limit comes into contact with the sensor, it may be
a break.
C: Compensating
element

D: Detecting element
Alumina
Oxidation catalyst

Platinum wire coil

0.5 - 0.7 mm
FixedresistanceFixedresistance

0.8 - 1.0 mm
Variable resistor for bridge
equilibrium adjustment
SW
E

Structure Diagram

VR
SwitchVariable resistor for bridge
voltage adjustment

Power supply

Basic Circuit[New Ceramic Type]
When a combustible gas burns on the surface of a highly active new ceramic oxidation catalyst in catalytic
combustion, the new ceramic-type sensor measures resultant temperature changes by measuring theresistance changes in the heat-resistant alloy wire coil.
The sensor consists of two elements: A detecting element having a heat-resistant alloy wire coil with anultrafine particle (new ceramic) oxidation catalyst sintered on it together with a carrier and a temperaturecompensating element with a mixture of gas-inert alumina and glass sintered on it.
When a combustible gas comes into contact with the surface of the detecting element with new ceramicoxidation catalyst sintered on it, the gas burns, causing the temperature to rise. In accordance with thistemperature change, there occurs a change in the resistance of a heat-resistant alloy wire coil that
constitutes the element. These resistance values are approximately proportional to gas concentrations.
From the changes in the resistance values, potential differences are obtained using a bridge circuit anddisplayed as gas concentrations on the meter.
C: Compensating
element

D: Detec ing element
AluminaHeat-resistant alloy wire coilHeat-resistant material(ceramic)

New ceramicoxidation catalyst
1.4 - 1.6 mm

1.3 - 1.8 mm

FixedresistanceFixedresistance

Variable resistor for bridge
equilibrium adjustment
SW
E

Structure Diagram

VR
Switch Power supply
Variable resistor for bridge
voltage adjustment

Basic Circuit
GD-D58 Series- 48 -

10 Product Specifications

10-2. Detection principle[Flow Sensor]
The flow sensor has a circuit that can output a contact signal when the flow rate drops below the preset
level.
The flow sensor is a hot-wire type with a Wheatstone bridge consisting of a detecting element,compensating element, and fixed resistance. Contained in a flame arrester container allows it to be flameproof.
When the drawn air or gas comes into contact with the heated detecting element, the detecting element
temperature changes due to the heat dissipation, and the electrical resistance of the element changes
according to the temperature changes. Since the resistance changes are in proportion to the gas flow
rates, the Wheatstone bridge circuit can identify the changes as the flow rate.
C: Compensating
element

D: Detec ing element

Fixed
resistance

VR

Fixed
resistance

Variable resistor for bridge
equilibrium adjustment
SW
E

Variable resistor for bridge
voltage adjustment

SwitchPower supply

Basic Circuit

Flow Sensor Appearance- 49 -

GD-D58 Series

11 Definition of Terms

10-2. Detection principle

11

Definition of Terms
Catalytic
combustion typeThis is a principle of the sensor installed in the Type GP.
See "10-2. Detection principle" for details.

New ceramicThis is a principle of the sensor installed in the Type NC.
See "10-2. Detection principle" for details.

Initial clear

Output from the detector head fluctuates for a while after turning on the power.
This is a function to prevent triggering alarm during that time.

Full scale%LEL
ppm
Calibration

GD-D58 Series

Maximum value of the detection range.
A unit which the lower explosive limit (LEL) of the combustible gas to be detected
is set to 100.
A concentration unit that means part per million of the combustible gas to be
detected.
Adjusts the readings to the calibration gas concentration value by using thecalibration gas.

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