Diffusion type Gas Detector
Model KD-12
Instruction Manual Keep this instruction manual where it is readily accessible.
 Thoroughly read this instruction manual before using the equipment so it can be usedsafely and correctly.
 This manual provides information concerning standard specifications. If the specificationsof your model are nonstandard, refer to the delivery specifications.

New Cosmos Electric Co., Ltd.
Instruction Manual No.
GAE-056-08
September 2022

 Nomenclature Replacement of Sensor Unit

See pages 5 to 7.

See pages 22 and 23.

 Wiring and Connecting
Methods

 Display and Operation in
Each ModeSee pages 13 to 16.

See page 19.

24 V
power
supplyIndicator

ShieldE.g., External
alarm

Ground terminals

 Maintenance Check andOperation Methods
See pages 21 to 28.

 Troubleshooting
See page 29.

Table of Contents
1.
2.
3.
4.

Introduction .................................................................................................................. 1
Precautions .................................................................................................................. 2Contents of Package ................................................................................................... 4External Dimensions and Nomenclature ..................................................................... 5
4-1. Main Unit .................................................................................................................. 5
4-2. Display and Control Blocks ...................................................................................... 6
4-3. Terminal Block .......................................................................................................... 7
5.
Installation.................................................................................................................... 8
5-1. Installation Method ................................................................................................... 8
5-2. Examples of Installation Positions .......................................................................... 11
5-3. Mounting of Optional items .................................................................................... 12
6.
Wiring Method............................................................................................................ 13
6-1. Wiring Work............................................................................................................ 13
6-2. Wiring and Connection........................................................................................... 14
7.
Precautions before Use ............................................................................................. 17
 In Case of Oxygen Deficiency ................................................................................... 17
8.
Display at Start-up (Initial Delay)................................................................................ 18
9.
Display and Operation in Each Mode ........................................................................ 19
10. Trouble Alarm ............................................................................................................. 20
11. Maintenance Check and Operation Method .............................................................. 21
11-1. Daily Inspection and Periodical Inspection ............................................................ 21
11-2. Replacement of Sensor Unit .................................................................................. 22
11-3. Calibration Method ................................................................................................. 24
 Maintenance Mode ......................................................................................................... 24
 Span Rough Adjustment ............................................................................................ 25 21.0 vol% Adjustment ................................................................................................ 26
 Full-scale and Alarm Set Value Display .................................................................... 27
 Test Mode .................................................................................................................. 28
12. Troubleshooting ......................................................................................................... 29
13.
Specifications ............................................................................................................. 30
14. Markings of explosion-proof....................................................................................... 31
15. Warranty ..................................................................................................................... 32
16. Detection principle ..................................................................................................... 33
17. Glossary ..................................................................................................................... 35

1. Introduction
 Thank you for purchasing the KD-12 Diffusion type Gas Detector.
 In order to ensure the correct and safe operation of this product, be sure to read thismanual before use.
 This product detects oxygen leaks and oxygen deficiency in working environments ofsemiconductor manufacturing plants. It displays the oxygen concentration and also
outputs an analog signal (4 to 20 mA DC) indicating the oxygen concentration to an
external device. If a preset oxygen concentration is reached, the red alarm lamp andalarm relays will operate, making this Detector useful in monitoring oxygen
concentrations.
 Maintenance and inspection are indispensable to the reliable performance of the Gas
Detection/Alarm System. Be sure to perform the maintenance checks described in thismanual.

Explanation of Symbols
The following symbols are used to indicate and classify precautions in this manual.

DANGER

Indicates information that, if not heeded, is likely to result in death orserious injury.

WARNING

Indicates information that, if not heeded, could possibly result in death orserious injury.

CAUTION

Indicates information that, if not heeded, could result in minor injury, or
damage to the product.

MEMO

Indicates advice on handling the product.

12. Precautions
 Read this manual completely and be sure you understand the information provided herein
before attempting to use the product.
 Abide by all applicable laws and regulations when using this product.

WARNING Be sure to ground the product to prevent electric shocks.
 If there is a gas leak alarm, take the necessary measures in accordance with yourcompany's regulations.
 The cable entry device and blanking elements shall be of ATEX/UKEx/IECEx certified in
type of explosion protection flameproof enclosure ‘’db’’, suitable for the condition of use
and correctly installed.
 Unused apertures shall be closed with suitable ATEX/UKEx/IECEx certified blanking
elements.
 Fastener type M5 x 16 shall have a yield stress factor of min. 450 N/mm2.

CAUTION All necessary work for the product including wiring and installation should be carried out
by suitably trained personnel in accordance with applicable code of practice.
 Inspection, maintenance and repair of the equipment should be carried out by suitablytrained personnel in accordance with applicable code of practice.
 Do not disassemble the product or modify the construction or electric circuits of the
product. Otherwise, the explosion-proof construction of the product may be adversely
affected.
 Be sure to provide a protective cover (optional) if the product is installed outdoors.
 Use the product in accordance with applicable laws and regulations.

 Due to the presence of high concentrations of SO2 and Cl2 gases, the sensor life
may be reduced and the error margin may increase.
 Measurements performed when the atmospheric pressure of the measurement
environment is different from standard atmospheric pressure (example, at a highaltitude) do not show the correct value because of pressure dependence.

2

Special Condition for Safe Use If used in an ATEX hazardous area, an ATEX-certified cable gland must be usedaccording to EN IEC 60079-0:2018 and EN 60079-1:2014. (Not included)
 If used in an UKEx hazardous area, it must be used a suitably certified cable gland for
UKEx requirements. (Not included)
 If used in an IECEx hazardous area, an IECEx-certified cable gland must be usedaccording to IEC 60079-0:2017 Edition 7.0 and IEC 60079-1:2014 Edition 7.0. (Notincluded) Fasteners (M5x16 hexagonal head screws) shall have yield stress of at least 450 N/mm2.
 Cable entry requirements for cable gland:
Thread size………………………… G3/4 or PF3/4
Minimum depth of engagement …. 10.86mm
Minimum thread engagement…….. 6 threads

 The dimensions of a flameproof joint between the case and the case cover of the KD-12
flameproof housing must meet the minimum requirements specified in EN/IEC60079-1.
Please contact the manufacturer for inspection, repair or adjustment of the flameproof
joint.

3

3. Contents of Package
 The product is provided with the following items. Make sure that none of these items is
missing.
 Although the product is packed and shipped with the utmost care, contact your New
Cosmos representative if there should be any damage or missing items.
Accessories

Optional items

Detector head
Accessory set
Two M5 screws: 2 pcs
M4 x 4 hexagon socket head screw:1pc

Protective cover (see note 2)
Horizontal type: KW-41A
Vertical type: KW-42A
PB-1 2B Pole Mounting Bracket (see note 2)
GCP-09 Calibration Cap (see note 2)
Z-001K Gas Calibration Kit
2 bulb hand pump
Capillary for 2 bulb hand pump

Hexagon wrench (nominal dia. 4): 1 pc
Instruction Manual (see note 1)
MJ-1 Magnetic Stick: 1 pc

Note: 1. A Instruction Manual is provided for each order.
2. The optional items are for use only with KD-12.

WARNING Do not use the magnetic stick for any purposes other than the operation of this product.
 Keep any magnets away from the equipment except MJ-1 magnetic stick.
 Keep in mind that when the magnetic stick attracts magnetic objects, tools, iron pieces,
etc., your hands may become pinched and injured.
 Do not touch the magnet if you are allergic to metal, otherwise your skin may becomechapped or reddened.
 Generally speaking, magnets break easily and the corrosion of the magnet progresses
from the fracture location. Fragments of the magnet may also get in your eyes or injure
your skin.
 The components of the magnetic stick may melt into water. Do not drink water exposed tothe magnetic stick.
 Keep the magnetic stick away from electronic medical devices, such as cardiac
pacemakers, or the magnetic stick may obstruct the normal operation of the device.

CAUTION Keep the magnetic stick away from magnetic tapes, floppy disks, and prepaid cards.
Otherwise, they may become magnetized and the information that they hold may be lost.
 Keep the magnetic stick away from high-precision devices, such as personal computers
and watches. Otherwise, they may malfunction.

44. External Dimensions and Nomenclature
4-1.

Main Unit(Dimensions are in mm)

Item

Component

Description/Function(1)

Case cover

---

(2)

Case

---

(3)

Sensor unit

Incorporates a built-in gas sensor.

(4)

Earth terminal(external)

Used for grounding the frame.

(5)

Status lights(3 places)

Indicate the status of the unit:
power (green), alarm (red), and fault (yellow)(6)

Magnetic witches(4 places)

Insert the magnetic stick into each magnetic switch opening tooperate.

(7)

Display

Displays the gas concentration, parameter value and status
message.

(8)

Cable entry

Thread size: G3/4 or PF3/4. Pitch=1.81mm.
Depth of engagement: 10.86mm.
Minimum engaged threads: 6 threads.
Applicable cable gland*1 must be provided by end user.

(9)

M5x16
To secure the case cover.
Hexagonal head
Use 4mm hex key wrench (included).
screws (4 places)(10)

M4x4 Hexagonal
set screw(2 places)

To secure the cable gland (cable fitting) and the sensor unit. Use
2mm hex key wrench (not included).

*1: Cable gland should be ATEX/UKEx-certified according to EN IEC 60079-0:2018 for use in an
ATEX/UKEx hazardous area, and EN 60079-1:2014, and IECEx-certified according to IEC
60079-0:2017 Edition 7.0 and IEC 60079-1:2014 Edition 7.0 for use in an IECEx hazardous area.

5

4-2.

Display and Control Blocks

Magnetic Switches
Use the magnetic stick (MJ-1) to operate the magnetic switches.
Item

Component

Description/Function(1)[MODE] switch

Changes the operation mode or cancels the current
operation.

(2)[ENTER] switch

Confirms a setting or executes an operation.

(3)[UP] switch

Increases the parameter value.

(4)[DOWN] switch

Decreases the parameter value.

Item
(5)

Component

Description/Function
Displays gas concentration, parameter value and status
message.

Display

Status Lights
Item

Component

Description/Function(6)[POWER] light (green)

When lit, the unit is on.

(7)[ALARM] light (red)When lit, alarm notification.

(8)[TROUBLE] light (yellow)

When lit, fault (device error) detected.

6

4-3.

Terminal Block

24V(+) 1
GND

2

Signal 3
ZA

4

ZC

5

POWER －
4～20mA＋E
Clamp

Groundterminal

Lever

Sensorconnector
O-ringNumber
1

Name

Description

24 V (+)

Power supply voltage (positive)

GND

Power supply voltage (-) and analog signal(negative) common

3

Signal4- to 20-mA (+) analog signal

4

ZA

5

ZC

2

External contact
Ground terminal

Used to ground the frame.

75. Installation
5-1.

Installation Method

WARNING The cable entry device and blanking elements shall be of ATEX/UKEx/IECEx
certified in type of explosion protection flameproof enclosure ‘’db’’, suitable for thecondition of use and correctly installed.
 If used in an ATEX hazardous area, an ATEX-certified cable gland must be usedaccording to EN IEC 60079-0:2018 and EN 60079-1:2014. (Not included)
 If used in an UKEx hazardous area, it must be used a suitably certified cable glandfor UKEx requirements. (Not included)
 If used in an IECEx hazardous area, an IECEx-certified cable gland must be usedaccording to IEC 60079-0:2017 Edition 7.0 and IEC 60079-1:2014 Edition 7.0.
(Not included)
 Unused apertures shall be closed with suitable ATEX/UKEx/IECEx certified
blanking elements.
 Fastener type M5 x 16 shall have a yield stress factor of min. 450 N/mm2.
 The dimensions of flameproof joint between casing and casing cover of KD-12
flameproof housing are exceeding the minimum requirements stated
EN/IEC60079-1. Please contact the manufacturer for inspection, repair and/or
adjustments of this flameproof.
 Cable entry requirements for cable gland and sensor:- Cable gland- Sensor

Thread size: G3/4 or PF3/4

Thread size: M27

Pitch: 1.81mm

Pitch: 1.5mm

Min. depth of engagement: 10.86mm

Min. depth of engagement: 8.25mm

Min. thread engagement: 6 threads

Min. thread engagement: 5.5 threads

 Securely tighten the hexagonal
set screws
to ensurethat no movement of the
Hexagonal
set screws(2 places)
cable gland is possible.
Screw Specifications
Size: M4x4
Screw length for securing cable gland: 3, 4, 5 or 6 mm
Screw length for securing sensor unit: 3 or 4 mmMaterial: Stainless steel

Note: The head of each screw shall be flush with the surface of the fitting.

8

CAUTION
 Be careful not to damage the gas detector when installing it. Otherwise, theexplosion-proof performance of the gas detector will be lost.
 Do not install the product in the following places.
- Places where the ambient temperature exceeds the operating temperature range(10C to 40C).
- Places where condensation occurs.
- Places where water is directly sprayed.
- Places subject to corrosive gas.
- Places near to devices generating high frequency and magnetism.
 Install the gas detector in places where can be maintained and inspected with ease.
 Install the gas detector in places free from vibration.
 Install the gas detector in places free from sudden temperature changes.
 Keep the gas detector free from impacts.
 When installing the gas detector outdoors, be sure to install the protective cover(optional).
 Mount the gas detector at a height where maintenance inspection can be performed
easily and considering the fact that oxygen deficiency (anoxia) occurs easily at aheight of 75 to 150 cm from the floor.

9 Mount the main unit to the wall with the M5 screws that are provided with the product. Be
sure to install the protective cover (optional) when mounting the main unit outdoors.
Mount the main unit with a 2B pole mounting bracket (optional) when mounting the main
unit to a 2B pole. Refer to 5-3 Mounting of Options for details of optional products.

(Dimensions are in mm)

 The casing cover of the gas detector needs be opened at the time of wiring. Therefore,
when installing the gas detector, provide sufficient space to enable the casing cover to beopened to at least 90°.

(Dimensions are in mm)

10

5-2.

Examples of Installation Positions

 Install the product in places where gas easily accumulates.

Places where gas easily accumulates.
Gas detector
Roof fan(Exhaust port)

Entrance(Suction port)

Entrances and windows(Suction and exhaust ports)

Gas detector
mounting
position

Side view

Plan view
Example of Installation Position

Partition
wall

Pipe
Valve

Detector

FlangeExample of Outdoor Installation Position

11

5-3.

Mounting of Optional items

 Protective Cover
(190)

(90)

(90)

(190)
M3 screw(1 place)M3 screw(1 place)
(190)

(190)

(Dimensions are in mm)

Horizontal Type (KW-41A)

Vertical Type (KW-42A)

CAUTION Secure the casing cover with M3 screws if strong winds are expected.

 2B Pole Mounting Bracket(Dimensions are in mm)

126. Wiring Method
6-1.

Wiring Work Be sure to provide explosion-proof wiring if the product is to be used in a hazardous area.

WARNING The cable entry device and blanking elements shall be of ATEX/UKEx/IECEx certified in
type of explosion protection flameproof enclosure ‘’db’’, suitable for the condition of use
and correctly installed.
 Unused apertures shall be closed with suitable ATEX/UKEx/IECEx certified blanking
elements.

CAUTIONAll necessary work for the product including wiring and installation should be carried out
by suitably trained personnel in accordance with applicable code of practice.

 Inspection, maintenance and repair of the equipment should be carried out by suitablytrained personnel in accordance with applicable code of practice.

Cable Work
 Use a shielded cable, such as CVV-S with a thickness of 1.25 to 2.00 mm2. Lay all cables
in protective tubes, such as metal conduits or carbon steel pipes, or other protective
structure, such as a concrete duct.
 When using the external contact function of the product, which requires a five-conductor
cable, make sure that the maximum diameter of the cable conductor is 1.25 mm2. Whenusing only the analog signal function, which requires a three-conductor cable, without theexternal contact function, make sure that the diameter of the cable conductor is 12.5 mm2
or 2.00 mm2.

13

6-2.

Wiring and Connection

WARNING Before opening the case cover of the gas detector, be sure to eliminate possible sourceof ignition. Disconnect the power supply to the detector and all devices connected to it(e.g. indicator unit and signal converter).
 Be sure to ground the product to prevent electric shocks.

 Use a conductor with a cross-sectional area of at least 4mm2 for external grounding.
 Place a plain flat washer between the case and the terminal.

CAUTION Wire the connecting terminals correctly.
 Separate connection cables from power lines as far as possible.
 When closing the casing cover, make sure that the power supply cords, harness, andO-ring are not caught in the casing cover.

Connecting Power Supply and Signal Wires Provide dedicated breakers, if needed, to lines that are connected to peripheral devices,such as indicator units and signal converters.
 Use a dedicated cable, such as CVV-S (with a thickness of 1.25 to 2.00 mm2).
 Make sure that the power supplied to the product is within the specified voltage range.
 Make sure that the load resistance of the signal line, including the resistance of the wire, is
300 ohm or less.

14

6-2.

Wiring and Connection (Continued)

MEMO If the main unit is grounded on the power supply side, do not connect a shielded cableto the ground terminal (E) in the gas detector, or otherwise two-point grounding will result.
Connection Example with Power Supply Side Grounded
KD-12R24V
power
supplyCVVS cable

Indicator

ShieldNot grounded

Groundterminals

External alarm

Ground terminal on
power supply side
Grounded

System Configuration Example
Single detector connected
Multiple detectors monitored
to indicator unit
togetherDetector
Detector

KD-12

Indicator unit

KD-12
Security
management system

V2M

KD-12
S-500

GAS
VISION

KD-12
Comprehensive gas
detection/alarm system

KD-12
For details, refer to the Instruction Manual of each device.

15

6-2.

Wiring and Connection (Continued)

Typical Connection Procedure(1)

Prepare a power supply that can provide 24 V.
(Do not turn on the power supply before wiring the main unit.)(2)

Loosen the hexagon socket bolts on the four corners of the main unit using theprovided hexagon wrench with a nominal diameter of 4 mm, and open the casing
cover of the main unit.

(3)

Press the lever of the terminal block with a flat-blade screwdriver.

(4)

The clamp will open. Insert the lead wire.

(5)

Connect the positive side of the power supply to the 24 V+ terminal.

(6)

Connect the negative side of the power supply to the GND terminal.

(7)

The lead wire will be automatically secured when the screwdriver is lifted.

(8)

Check that the power supply cords are securely connected to the terminals. This
completes the power supply preparations.

(9)

Wire the analog signal and external contact terminals, if required.

(10) Tighten the hexagon socket bolts (tightening torque: 0.8-2.4 Nm) on the four cornersof the main unit and close the casing cover of the main unit.

CAUTION

When lowering the lever of the terminal block, be careful not to allow the flat-blade
screwdriver to slip off of the lever. Otherwise, the flat-blade screwdriver may damage thesensor unit code or circuit board.

When closing the casing cover, make sure that the power supply cord, harness, and O-ringare not caught by the casing cover.

16

7. Precautions before Use

CAUTION Before turning ON any of the devices (e.g., indicator unit, signal converter) connected tothe product, recheck that all of the connections are correct. Make sure that the gas
detector and indicator unit or signal converter, in particular, are connected properly.

 In Case of Oxygen Deficiency

DANGER Always enter the detection site after making sure that it has approximately the same
oxygen concentration as the atmosphere. If the concentration of oxygen is below 18.0
vol%, it may result in death due to anoxia.

WARNING If there is a alarm, take the necessary measures specified by your company.
 If a gas leak occurs indoors, open the windows and doors to ventilate the room.
 Check the gas leakage location and promptly take the necessary measures.
Measure the gas concentration with a portable gas detector and confirm the safety before
entering the detection site.

17

8.

Display at Start-up (Initial Delay)

CAUTION If the sensor output is not stable, the external contact point may operate after the initialdelay. Release the interlock of the external equipment if necessary.
 During the initial delay, there is a fixed output of the analog signal corresponding to thestandard oxygen concentration 21.0 vol%. The external contact does not operate.

(1)

When the power supply is turned ON, all of the indicator lamps (green, red, and yellow
lamps) and the display block are lit.

(2)

While the indicator lamps (green, red, and yellow lamps) are lit, the following items will
be lit for approximately 1 second each.
Software version number (of the main unit)
Full scaleAlarm set value

ex) 【

】

ex) 【

】

ex) 【

】

(3)

Then the POWER indicator (green lamp) will be flashed for approximately 1 minute.

(4)

When the POWER indicator is lit, the start-up of the main unit is completed and themain unit will be in gas monitor mode.

MEMO

 The operation with the magnet stick is not available during the initial delay.
 The initial delay lasts for approx. 10 seconds after the power supply is turned ON.
 More than one minute after turning on the detector, make the zero adjustment and span
adjustment.Refer to 11.3 Calibration Method for the adjustments.

18

9.

Display and Operation in Each Mode
In excess of alarm set value
At start-up(Initial delay)
Green lamp
flashes

Maintenance mode

Gas monitor
mode

Green
lamp is
ON

Red
lamp
flashes

Test mode

Gas monitor
mode

Red lamp
Green flashes
lamp isON

Test mode
Red lamp
flashes

Green lamp
is ON

Contents
of display[
Gas
concentration isdisplayed.

Gas
concentration isdisplayed.

A full-scale testfrom 0% to 110%is possible.

][Gas
concentration]

Displayedalternately

Analogsignal4 to 20 mA

Contact
operation

Fixed at 4 mA

Does notoperate (OFF).

Value that is
proportional to
the gasconcentration is
outputOperates (ON).

[][Test value]

Displayedalternately

Test value is
outputValue that is
proportional
to the gas
concentration
is output

Test value is
output.

Operates (ON).

Does notoperate(OFF).

Does notoperate(OFF).

19

10.

Trouble Alarm

 The product has a self-inspection function, and the trouble alarm will operate if a problem
occurs.
 The product will inform the user of the problem details with the display shown in thefollowing table when the trouble alarm operates.
 When the trouble alarm is generated, the analog signal will be approximately 0.9 mA or
below.
Screendisplay

Troubleindicator

Problemdetails

Yellowlamp
flashes

Power supply
voltage droperror

The power supply
voltage is low.

Check the power supply
voltage.

Yellowlamp
flashesOver full scale

The span adjustment
may not be correct.

Make a span
adjustment again.

The sensor connector is
disconnected or thesensor wire has broken.

Check that the sensor
and the sensor
connector are securely
connected.

Yellowlamp
flashesSensorZero error

Probable cause

The sensor output is low.

Lamp isOFF

Spanadjustment
error

RemedyMake the zero point
adjustment with the gas
doesn't lie between air
around the equipment.

The Detector may nothave been surroundedwith clean air during
span adjustment.

After checking theenvironment around the
Detector, make the 21.0
vol% adjustment again.
If the Detector stillcannot be adjusted,make the span roughadjustment.

The life expectancy ofthe sensor may have
expired.

Replace the sensor unit.

 If a screen other than the above is displayed, refer to the 12. Troubleshooting section. If
the product does not reset to normal operation after taking the measures shown in thetable or if the problem is not listed in the table, contact your local representative.
 If the product goes into any unintended mode during adjustment or setting, cease
operating the product and contact your local representative..

20

11.

Maintenance Check and Operation Method11-1. Daily Inspection and Periodical Inspection
 Daily inspections are conducted by the user, while periodical inspections are conductedby your local representative.

Daily
inspection

Frequency

Checking item

At least once
per month

Visualinspection

Alarm operation
test
Once permonth
Periodical
inspection

Once peryear

Contents of inspection▪ The status of lamp (green POWER
indicator) is lit.
▪ The concentration display of the gas
concentration indicator.
▪ Clogging of sensor unit mesh.
▪ Corrosion of sensor unit mesh.
▪ Corrosion of the main unit.
▪ Corrosion of mounting screw.
If a failure is found, replace the parts.
Make sure that the alarm of the Detector isoperating properly. For details about how to
perform the alarm operation test, refer to Test
Mode.

21.0 vol%confirmation

Make sure that the displayed value in clean
air is 21.0 vol%. If not, perform the span
adjustment. For details about how to performthe span adjustment, refer to 21.0 vol%Adjustment.

Replace the
Oxygen sensor
unit

Replace the oxygen sensor, and thencalibrate it. For details about how to replaceand calibrate the sensor, refer to 11-2.
Replacement of Sensor Unit and 11-3.
Calibration Method.

Periodical Inspections
In order to maintain the reliability of the gas detection/alarm system, it is extremely important
to conduct maintenance and inspections.
It is highly recommended that you consider periodical inspections under a maintenancecontract with your local representative.

21

11-2. Replacement of Sensor UnitWARNING Be sure to turn OFF the indicator unit, signal converter or main body equipment before
replacing a sensor unit. Otherwise, they may become a source of ignition.
 Be sure that the sensor and the sensor connector have been firmly connected to thedetector before the power is turned on. If the sensor and the detector are incorrectly
connected, the detector cannot detect gas.
 The dimensions of flameproof joint between casing and casing cover of KD-12 flameproof
housing are exceeding the minimum requirements stated EN/IEC60079-1. Please contact
the manufacturer for inspection, repair and/or adjustments of this flameproof.
？

CAUTION Only your local representative’s maintenance service members or personnel who havecompleted a maintenance seminar can replace the sensor unit.
 The external contact may operate when replacing the sensor unit if the sensor output is
not stable. Release the interlocks of the external devices if needed.
 Replace the oxygen sensor (model: OS-3M-G) once a year.
 The “Use by” date of the sensor unit is stated on its package. Use it before the “Use by”date.
 The oxygen sensor has positive and negative polarity. Be sure to check the polarity
when replacing the sensor.
 When setting the oxygen sensor, make sure that the sensor pins do not damage thesensor socket, which may result in a loose connection.
 Make sure that the mesh of the sensor casing is free of dirt or dust. Clean the meshbefore installing the sensor casing to the detector.
 Handle the sensor with care. Do not drop or throw it. Dropping or throwing the sensor
may cause liquid to leak or may result in malfunctioning.
Be sure to handle the sensor unit with care. Do not drop or throw the sensor unit. Failure
to do so may lead to broken wire or sensor failure.

 When removing or mounting the sensor unit, do not twist the harness of the sensor
connector.
 When closing the casing cover, make sure that the power supply cord, harness, or O-ringis not caught by the casing cover.

MEMO Return the used sensor unit to your local representative.
 After replacing the sensor, stabilize the sensor by turning it ON for approx. 1 minute, andthen perform the span adjustment.
 To adjust the gas concentration after replacing the sensor, always perform the spanrough adjustment first, followed by the 21.0 vol% adjustment
 If any error is displayed, refer to 10. Trouble Alarm.

2211-2.
1)
2)
3)

4)

5)

Replacement of Sensor Unit (Continued)
Turn OFF the power supply to the Detector.
Remove the sensor casing cover by rotating it in the direction of the arrow. (See thephotograph below on the left.)
Pull down the sensor to remove it. (See the photograph below on the right.)

Connect the sensor. (See the photograph below on the left.)
Insert the pins (+) (-) of the oxygen sensor to match the sockets (+) (-) of the sensor
circuit board, and then press the sensor lightly. For details, see the following figures.
Make sure that the pins of the oxygen sensor are straight with respect to the socketsof the sensor circuit board, and then push in the sensor.
Finally, close the sensor casing cover. (See the photograph below on the right.)
Make sure that no dirt or dust is trapped in the sintered wire mesh of the sensor
casing, and install the sensor after cleaning the wire mesh.

【Reference Figures】
Pin (- polarity)

Pin (+ polarity)

Socket (+ polarity) Socket (- polarity)

Sensor exterior
Oxygen sensor back surface

As seen from above

O2

Sensor circuit board

As seen from the side

Oxygen sensor

O2

Sensor circuit board
As seen from the side

The Sensor Pressed in Properly

As seen from above

The Sensor Pressed in Incorrectly2311-3. Calibration Method
 Maintenance Mode

CAUTION While in maintenance mode, the external contact does not operate when theconcentration of gas reaches or exceeds the alarm set value. The product inmaintenance mode maintains the current status while the display shows [].
This mode is canceled by repeating the same operation(1 to 4), turning the product OFF,or waiting 8 hours.

(1)

While in gas monitor mode, press the MODE switch of the main unit first. Then press
the UP switch with the magnetic stick within approximately 2 seconds.

(2)

The main unit displays
first, followed by.
(The product is ready to work but nothing has been operated.)(3)

Press the UP or DOWN switch of the main unit with the magnetic stick and adjust thevalue to .

[][Gas concentration](4)

Press the ENTER switch of the main unit.

(5)

When the above items are displayed alternately, the product has been set tomaintenance mode.

(6)

Upon completion of this mode, the product will automatically return to gas monitor
mode.

(7)

While

(8)

This mode will be canceled by repeating the same operation (1 to 4 above), turning
the product OFF, or waiting for 8 hours.

is displayed, the maintenance mode is being executed.

Carefully handle and make settings with the magnetic stick because the magnet is very
powerful. For details, refer to 3. Contents of Package.

24

 Span Rough Adjustment
This adjustment mode is used after replacing the sensor or when adjustment cannot be
performed with the 21.0 vol% adjustment.

CAUTION The external contact may operate during span rough adjustment.
Before performing span rough adjustment, set the product to maintenance mode orrelease the interlocks of the external devices if needed.
 Only your local representative’s maintenance service members or personnel who havecompleted a maintenance seminar can perform span rough adjustment.

1)
2)
3)
4)
5)
6)

7)

8)
9)
10)

Apply calibration gas corresponding to the Detector.
Sufficiently stabilize the gas.
While in gas monitor mode, press the MODE switch on the Detector first. Then press
the UP switch with the magnetic stick within approximately 2 seconds.
Press the UP or DOWN switch on the Detector with the magnetic stick and adjust thevalue to【】.
Press the ENTER switch on the Detector to start the operation.
The Detector displays 【】 first, and then displays the present gas
concentration.
Press the UP or DOWN switch on the Detector with the magnetic stick, and adjust thedisplay of the Detector to a value close to the actual span gas concentration. In thepresence of atmospheric air, adjust the display to 21.0 vol%.
After adjusting the display on the Detector to a value close to the span gas
concentration, press the ENTER switch on the Detector.
The span rough adjustment is completed when 【】 is displayed.
On completion of the span rough adjustment, the Detector will automatically return togas monitor mode.

MEMO
Precise adjustment is not performed by the span rough adjustment alone. Be sure to
perform the 21.0 vol% adjustment after the span rough adjustment.
If an error is displayed, refer to 10. Trouble Alarm.
Carefully handle and make settings with the magnetic stick because the magnet is very
powerful. For details, refer to 3. Contents of Package.

25

 21.0 vol% Adjustment
・This span adjustment mode is used in atmospheric air during periodic inspection.

WARNING▪ Always perform the 21.0 vol% adjustment in clean air. If you perform the 21.0 vol%adjustment in a gas atmosphere, the value of oxygen concentration output will be displayed
incorrectly.

1)
2)
3)

4)

Make sure that the Detector is surrounded with clean air.
While in gas monitor mode, press the MODE switch on the Detector first. Thenpress the UP switch with the magnetic stick within approximately 2 seconds.
The Detector displays 【】 first, followed by 【】 . (This
procedure assumes that no operation has been performed after turning ON thepower supply.)
Press the UP or DOWN switch on the Detector with the magnetic stick andadjust the value to 【
】.

5)

6)
7)

8)

Press the ENTER switch on the Detector to start the operation.
When the operation starts, the following are displayed, and the Detector is
automatically adjusted to 21.0 vol%.
【】↓【 Current displayed value 】
↓
【
】
↓
【
】
On completion of the span rough adjustment, the Detector will automatically
return to gas monitor mode.

26 Full-scale and Alarm Set Value Display
 The full-scale and alarm set values are only displayed. They cannot be changed.

(1)

While in gas monitor mode, press the MODE switch of the main unit first. Then press
the UP switch with the magnetic stick within approximately 2 seconds.

(2)

The main unit displays
first, and displays.
(The product is ready to work but nothing has been operated.)
Example: After zero adjustment,
will be displayed.

(3)

Press the UP or DOWN switch of the main unit with the magnetic stick and adjust thevalue to.

(4)

Press the ENTER switch of the main unit.

↓↓
Full scale↓↓
Alarm set value(5)

When the above items are displayed in sequence and repeatedly, the user can checkthe full-scale and alarm set values.

(6)

After the full-scale and alarm set values are displayed, the product will automatically
return to gas monitor mode.
 Carefully handle and make settings with the magnetic stick because the magnet isvery powerful. For details, refer to 3. Contents of Package.

27

 Test Mode
・Test values are adjusted and used for tests in this mode.

CAUTION The external contacts may operate while the Detector is in test mode.
Before changing the Detector to test mode, set the Detector to maintenance mode as
required. Also, release interlocks with external devices as required.
1)
2)

3)
4)

5)

6)

7)
8)

・

While in gas monitor mode, press the MODE switch on the Detector first. Thenpress the UP switch with the magnetic stick within approximately 2 seconds.
The Detector displays 【】 first, followed by 【】. (This
procedure assumes that the startup process has been completed but nooperation has been performed.)Press the UP or DOWN switch on the Detector with the magnetic stick andadjust the value to 【】.
Press the ENTER switch on the Detector to start the operation.

When the operation starts, the following value is displayed.
【】↓【 Test value 】
The test operation of the Detector can be performed in a concentration range
from 0% to 110% of full scale. (The test operation of the Detector is possible ina concentration range from 0.0 vol% to 27.5 vol% if the full scale of the
Detector is 25 vol%.)Press the UP or DOWN switch on the Detector and set the desired inspection
concentration. The test will start. If the setting is outside the operating range,【】 or 【】 will be displayed.
To end the test mode, press the ENTER or MODE switch. Text mode will be
ended.
If the ENTER switch is pressed to end test mode, the test value will be saved.
If the MODE switch is pressed to end test mode, the previously saved value
will remain.

Carefully handle and make settings with the magnetic stick because the magnet isvery powerful. For details, refer to 3. Contents of Package.

28

12.

Troubleshooting Before requesting repairs, refer to the following table. Consult your New Cosmos
representative if the product does not return to normal after taking the corresponding
remedies shown below or if the defective condition is not found in the table.
 If the product goes into an unintended mode at the adjustment or setting stage, stop
operating the product immediately and consult the system administrator.
Defective condition

Probable cause

The green power lamp is
not lit.

The yellow lamp to indicate
an error is flashed and theerror code is displayed.

The detected gas
concentration andare flashingalternately.

There is no alarm contact
output.

RemedyIncorrect wiring
connection.

Check and redo thewiring.

Reference page
P. 15
Wiring andConnection

Check the power supply
Low-voltage
voltage.
state

The product is inmaintenance mode.

Return the product to gas P. 24
monitor mode.
Maintenance Mode

The product is inmaintenance mode.

Return the product to gas P. 24
monitor mode.
Maintenance mode

Incorrect wiring
connection.

P. 15
Check and reconnect the
Wiring andwiring.
Connection

The alarm point setting is
Check the alarm setting.
wrong.
The analog signal does not The product is in testchange.
mode.

P. 27
Full-scale andAlarm Set Display

Return the product to gas P. 28
monitor mode.
Test mode

A value andflashing alternately.

The concentration of gas
are The sensor output is high. is in excess of the fullscale. Check the ambientenvironment.

A value andflashing alternately.

The sensor and sensor
Make sure that the sensor
are connector are not inserted and sensor connector areproperly. The sensor isinserted properly.
connected backward.

The product is operated
No adjustment or setting isduring the initial delay
possible.
time.

29

Operate the product after P. 18
the 30-seconds initial
Display at Start-up
delay time.
(Initial Delay)

13. Specifications
Model

KD-12

Detection principle

Galvanic cell sensor

Sampling method

Diffusion type

Detection gas

O2 (Oxygen)

Detection range

0 to 25 vol%Gas concentration
display

Four-digit digital LED display

Alarm set value

18 vol%Alarm accuracy±1.0 vol% of the displayed value

Alarm delay

5 seconds or less to reach 18vol% by coming into contact with oxygen gas
having a concentration of 10vol%. (at 20 +/- 2 C)

Warning display

 Gas alarm (one stage only):
Red LED lamp flashes
 Trouble alarm (sensor disconnection, sensor zero drop, power supply voltage
error, or internal EEPROM communication error):
Yellow LED lamp flashes

External output

Gas concentration analog signal
 4 to 20 mA DC (common to the negative side of power supply)
 0.9 mA DC or less at the time of Trouble alarm.
 Make sure that the load resistance of the analog signal is less than 300 ohm
including the wiring resistance.
Gas alarm contact (one stage only) 1a no-voltage contact output/Non-latching Rated load: 0.5 A at 250 VAC or 0.5 A at 30 VDC (resistance load)

Equipment or Protective Directive 2014/34/EU
System intended for
SI 2016 No.1107
use in Potentially
Explosive Atmospheres
Explosion-proof class

II 2 G Ex db IIC T5 Gb (ATEX)II 2 G Ex db IIC T5 Gb (UKEx)
Ex db IIC T5 Gb (IECEx)

Approvals

EU-Type Examination Certificate Number : DEMKO 08 ATEX 143870 X(CE 2776
II 2 G Ex db IIC T5 Gb)
UKEx Examination certificate: CML 21UKEX11353X(UKCA 2503
II 2 G Ex db IIC T5 Gb)
EMC : EN61000-6-4:2007+A1:2011, EN50270:2015 - Type 2
Performance testing: The measuring function of the KD-12 gas detector for
explosion protection, according to Annex II clause 1.5.5, 1.5.6 and 1.5.7 of the
Directive 2014/34/EU, is not covered in this certificate.
IECEx : ULD 13.0001X (Ex db IIC T5 Gb)

Harmonised/Designated standards

EN IEC 60079-0:2018, EN 60079-1:2014
IEC 60079-0:2017 Edition 7.0, IEC 60079-1:2014 Edition 7.0

Degree of protection

IP65 (Exterior)

Applicable cable

Cable outer diameter (10 to 13 mm)
 In the case of a 5-conductor cable (for power supply, gas concentration
analog signal, and gas alarm contact): CVV-S 1.25 mm2.
 In the case of a 3-conductor cable (for power supply and gas concentration
analog signal) CVV-S 2 mm2 or 1.25 mm2

30

Operating temperatureand humidity ranges

 Temperature: 10C to 40C Humidity 30% to 85% RH(No radical temperature or humidity changes and no condensation)

Power supply

24VDC (18 to 30 VDC)

Power consumption

3W max.

Size

128 (W) x 120 (H) x 68 (D) mm (excluding protruding parts)

WeightApprox. 1.3kg

Mounting method

Wall mounting

The above specifications are subject to change without notice.
If your specifications are nonstandard, refer to the delivery specifications.

14.

Markings of explosion-proof-Nameplate detail-Serial number label detail-Rated label detail-Certificate label detail-Warning label detail-Harmonised/Designated standards
EN IEC 60079-0:2018
EN 60079-1:2014
IEC 60079-0:2017 Edition 7.0
IEC 60079-1:2014 Edition 7.0

31

15.

Warranty

New Cosmos Electric Company Limited (hereafter referred to as “New Cosmos”) offers thefollowing as the sole and exclusive limited warranty available to the Customer.
This warranty is in lieu of, and the Customer waives, all other warranties of any kind or
nature, expressed or implied, including without limitation any warranty for merchantability or
fitness for a particular purpose. The remedies set forth herein are exclusive.
New Cosmos warrants to the original purchaser (Customer) and no other person or entitythat the gas detection product supplied by New Cosmos shall be free from defects inmaterials and workmanship for a period of one (1) year from the date of purchase. This
warranty does not apply to consumables, including but not limited to fuses and filters.
Certain other accessories not specifically listed here may have different warranty periods.
If after examination of an allegedly defective product returned to New Cosmos, with freight
prepaid, should it be found that the product fails to conform to this warranty, the Customer’s
only remedy and New Cosmos’s only obligation shall be, at New Cosmos’s sole discretion,
replacement or repair of the non-conforming product or refund of the original purchase priceof the non-conforming product. In no event shall New Cosmos be liable for any other special,incidental, or consequential damages or losses of any kind whatsoever, including but notlimited to loss of anticipated profits and any other loss caused by reason of non-operation of
the product.
This warranty is valid only if the product is maintained and used in accordance with New
Cosmos’s instructions and recommendations. New Cosmos shall be released from all
obligations under this warranty in the event repairs or modifications are made by persons
other than its own or authorized service personnel or if the warranty claim results fromphysical abuse or misuse of the product.

32

16.

Detection principle
Galvanic Cell Sensor

The galvanic cell sensor consists of noble metal (Pt, Ag) electrode, a base metal (Pb)electrode, and electrolyte. The noble metal electrode contacts the air through a Teflon
membrane.
Since a potential difference is produced between the two electrodes, the following reaction
occurs when a load resistor is connected:

Noble metal electrodeBase metal electrodeO2+2H2O+4e4OH
2Pb2Pb2++4eAs a result, a current proportional to the concentration of oxygen in the air flows from thenoble metal electrode to the base metal electrode through an external circuit. Since thecurrent generated is dependent on temperature, a thermistor is used to compensate for theatmospheric temperature changes.

Thermistor
OutputResistor

O2 sensor

Figure 10

Note
The galvanic cell sensor gives an output according to the partial pressure of the oxygen in
the air (the oxygen concentration is usually 21vol%.) Therefore, when the atmosphericpressure changes, the partial pressure of the oxygen will change, and when there is nochange in the oxygen concentration (21vol%), this may effect the output values from thesensor.

33

17.

Glossary

Detector:

A unit that detects gas concentration and converts it to electric
signals.

Diffusion type:

A method to detect gas by utilizing convection and diffusion ofgas.

Explosion proof construction:

A totally enclosed structure. When an explosive gas

explodes in a container, the container can resist the pressure
and prevent the ignition of explosive gases outside of it.
Gas to be detected:

Gas that is detected and indicated which sets off an alarm.

Detection range:

Range of gas’s concentration that can be indicated and set off
an alarm.

Operating temperature and humidity ranges: The ranges of temperature and humidity
within which performance and functionality can be maintained
during usage of the Detector.
Maintenance and inspections:

Work to guarantee that the equipment perform its

required functions.
Calibration gas:Gas used to calibrate scales of the equipment.

Hazardous area:

An area in a plant or facility with a hazardous atmosphere
where explosive gases may mix with air and explode or start afire. An area where gas may be present.

Non hazardous area:

An area where electric equipment that has no potential to createa hazardous atmosphere.

Hazardous atmosphere:

Atmosphere within the explosive limit where explosive gas andair are mixed.

(Quoted from gas detection terms and detector tube gas meter terms used by the Industrial
Gas Detector Alarm Association.)34

Manual Revision History
Edition No.

Date

Revision

GAE-056-00

July 201400

GAE-056-01

November 2016

01

GAE-056-02

August 201702

GAE-056-03

October 201803

GAE-056-04

January 201904

GAE-056-05

July 201905

GAE-056-06

December 201906

GAE-056-07

April 2021

07

GAE-056-08
September 2022
08
Additional copies of this Instruction Manual are available.
Contact the following address for ordering information.

Distributor:

Manufacturer:
NEW COSMOS ELECTRIC CO., LTD.
2-5-4 Mitsuya-naka, Yodogawa-ku
Osaka 532-0036, Japan
URL: http://www.newcosmos-global.com