Riken Keiki GD-F4A-SC-A User manual

Oxygen Gas Detector Head
GD-F4A-SC-A
Operating Manual
(PT2-152)
PT2E-2510

[OPERATING PRECAUTIONS]
This is a fixed type gas detector (head) and alarm instrument to detect oxygen gas in air. The
gas alarm instrument is a safety instrument, not an analyzer nor measuring instrument to make
quantitative and qualitative analysis or measurement.
Please understand following points and use this detector head correctly.
1. The indication on this detector has some changes against fluctuation of atmospheric
pressure. Especially, take care about alarm action at the time of depression caused by
typhoon.
It may also fluctuate against the environmental (temperature, humidity, etc.) change around
detector head.
2. Alarm level for gas alarm instrument shall be set within the performance of the instrument.
Our standard alarm level is 18% by volume for the prevention of oxygen deficiency.
3. This is not control equipment, but a safety instrument.
Use the alarm contact from gas alarm instrument only for external alarm light or buzzer.
And the analog output signal shall be used only for external indicator or recorder.
We do not assume liability for any accident or damage caused by other control purpose than
the above.
4. To maintain the performance of this gas detector, the regular maintenance service including
the regular parts replacement and adjustment described in this manual shall be required.
Also every 6 months regular maintenance and gas calibration are required since this is a
safety instrument.

TABLE OF CONTENTS
１．OUTLINE OF THE PRODUCT
１－１． Preface ………………………………………………………………………… 1
１－２． Purpose of use ………………………………………………………………… 1
１－３． Definition of DANGER, WARNING, CAUTION and NOTE…………………… 1
２．IMPORTANT INSTRUCTIONS FOR THE SAFETY
２－１． Danger cases…………………………………………………………………… 2
２－２． Warning cases…………………………………………………………………… 2
２－３． Caution cases…………………………………………………………………… 2
２－４． Caution for explosion proof (In case of intrinsically safe design)…………… 2
３．PRODUCT COMPONENTS
３－１． External drawing………………………………………………………………… 3
３－２． Name of each part and functions……………………………………………… 4
３－３． System composition …………………………………………………………… 4
４．HOW TO USE
４－１． Before using the detector head………………………………………………… 7
４－２． Precautions for installation points……………………………………………… 7
４－３． Maintenance space……………………………………………………………… 7
４－４． How to install …………………………………………………………………… 8
４－５． Caution at wiring construction…………………………………………………… 8
４－６． Applicable cable………………………………………………………………… 8
４－７． Example of cable connection…………………………………………………… 8
４－８． Caution at piping works…………………………………………………………… 10
４－９． Example of piping connection…………………………………………………… 10
５．HOW TO OPERATE
５－１． Preparation for start up………………………………………………………… 12
５－２． How to start the detector head………………………………………………… 12
５－３． How to exit……………………………………………………………………… 12
６．MAINTENANCE
６－１． Maintenance intervals and items………………………………………………… 13
６－２． Calibration
６－２－１． Required kit and tools for calibration ………………………………… 14
６－２－２． Performing a zero adjustment ………………………………………… 14
６－２－３． Performing a span adjustment ………………………………………… 14
６－３． Replacing the sensor
６－３－１． Replacement intervals of the sensor ………………………………… 15
６－３－２． How to replace the sensor……………………………………………… 16
６－４． Storage or treatment when not in use for a long period………………………… 17
６－５． List of recommendable spare parts for regular replacement…………………… 17
７．STORAGE, RELOCATION AND DISPOSAL
７－１． Procedures to storage the detector head or leave it for a long time …… 18
７－２． Procedures to relocate the detector head or use it again ………………… 18
７－３． Disposal of products ………………………………………………………… 18
８．MEASURES AT ABNORMAL CASE
８－１． Responding to trouble alarm ……………………………………………… 19
８－２． Before it is thought to be a trouble………………………………………… 19
９．PRODUCT SPECIFICATIONS
９－１． Standard specifications ………………………………………………… 20
９－２． Standard accessories ……………………………………………………
20
９－３． Optional accessories …………………………………………………… 20
９－４． Detection principle ……………………………………………………… 21
１０．DEFINITION OF TERMS………………………………………………… 22

1
１．OUTLINE OF THE PRODUCT
１－１．Preface
Thank you for purchasing our fixed type Oxygen Detector Head GD-F4A-SC-A.
First of all, verify that the model number of this product is identical with specifications
described in this manual. This manual is a guide to operation of the GD-F4A-SC-A. All
parsons who use this unit for the first time and who has ever used this unit are requested to
read through the manual to understand the content before use.
１－２．Purpose of use
This is a suction(flow-through) type oxygen detector head applying the galvanic cell type
oxygen sensor and is used in combination with indicator / alarm unit to show oxygen content.
Read the operating manual for indicator / alarm unit as well as this manual.
This unit is designed as drip-proof construction for outdoor installation.
Also, it can be used as intrinsically safe system in combination with zener barrier (option) to
be able to install in hazardous area.
１－３．Definition of DANGER, WARNING, CAUTION and NOTE
This manual contains the following headings to ensure the safe and effective operation.
This message indicates that improper handling may cause serious
damage on life, health or assets.
This message indicates that improper handling may cause serious
damage on health or assets.
This message indicates that improper handling may cause minor
damage on health or assets.
This message indicates advice on handling.
DANGER
WARNING
CAUTION
* NOTE

2
２. IMPORTANT INSTRUCTIONS FOR THE SAFETY
２－１．Danger cases
２－２．Warning cases
２－３．Caution cases
２－４．Caution for explosion proof (In case of intrinsically safe design)
In case of non-explosion poof system, do not use this unit at the place where combustible gas
may exist.
・Do not cut the wire for protective ground both inside and outside of instrument. Or, do not
disconnect the connection of the ground terminals.
・Before starting the operation, check if any defect is not found on the protective grounding.
・If there is any defect on the protective functions such as protective grounding, do not start the
operation.
・It is very dangerous if the instrument gives oxygen deficiency alarm.
Take appropriate measures based on your judgment at that time.
・Perform gas calibration at proper interval.
・Do not change or remodel the circuit/structure of this unit.
・Do not disassemble the sensor since there is a electrolyte inside.
If your finger touches the electrolyte, wash your finger away with water immediately.
WARNING
・Do not use a walky-talky around the instrument.
The indication might be affected by the electromagnetic wave generated by the
walky-talky if it is used near the instrument. When the walky-talky is used, be away
enough from the instrument not to affect.
・Do not control other equipment by using outputs of this detector.
This is not a control equipment. It is prohibited to control other equipment by using
outputs of this detector.
CAUTION
・Do not use this detector head expect for the measurement of oxygen content in a mixture of air
and combustible gas or vapors, or a mixture of air and toxic gases.
・When cleaning this unit, do not use dry cloth but use the wet cloth not to change the static
electricity on plastic part.
CAUTION
DANGER

4
３－２．Name of each part and functions
① Oxygen sensor : Galvanic type sensor to detect oxygen content.
② Sensor holder : This is a retainer to hold the oxygen sensor
(equipped filter inside).
③ Sensor lead wires : Lead wires for oxygen signal outputs.
④ Terminal strip 1 : Relayed terminal for sensor lead wires and external cable.
⑤ Cable gland : Entrance to lead the cable (φ8 - φ11mm) from outside.
⑥ Hinge : Hinge for front door.
⑦ Lock : Lock for front door.
⑧ Mounting hole : Mounting hole to fix this unit on the wall surface.
⑨ Terminal strip 2 : Relayed terminal for input/output signal use to the signal converter.
⑩ 4mA adjusting hole : VR hole to adjust 4 mA of 4-20mA output(factory set)
⑪ SPAN adjusting hole : VR hole to adjust SPAN
⑫ ZERO adjusting hole : VR hole to adjust ZERO
⑬ Front door : Front door for the unit
⑭ Signal converter : Circuit unit to convert the sensor output into 4-20mA
⑮ Protective earth bolt : Bolt for protective grounding.
３－３．
System composition
(1) Intrinsically safe system
Detector
head
Zener barrier
Indicator
/alarm
unit
Hazardous area Non-hazardous area
In-between head and zener barrier :
CVVS 1.25mm2 2-core or equivalent (max 250m)
However, that of head and indicator/alarm unit :
CVVS 1.25mm2 2-core or equivalent (max 2km)
４－２０ｍＡ
①
②
③
④
⑤
⑥
⑦
⑧
⑨
⑩
⑪ ⑫
⑬
⑭
⑮

5
1. The oxygen detector shall be used as following composition.
2. The safety retainer to be connected with oxygen detector shall have linear characteristics
and be passed the type approval as it is.
Also it shall satisfy the following conditions.
(1) Rating of safety retainer
Max voltage of intrinsic-safety circuit: Below 28V
Max current of intrinsic-safety circuit: Below 93 mA
Max power of intrinsic- safety circuit: Below 0.65W
(2) Performance division and group
Performance division: ia
Group : ⅡC
(3) Relations between allowable inductance (Lo) and allowable capacitance (Co)
of intrinsic-safety circuit, and external wiring inductance (Lw) and capacitance(Cw)
of intrinsic-safety circuit.
Lo ≧ Li + Lw
Co ≧ C + Cw
3. When making wiring connection for intrinsic-safety circuit, take care not to induce an electric
current and voltage which will spoil the performance of intrinsically safe by the
electromagnetic induction or electrostatic induction to the intrinsic-safety circuit.
WARNING
！
Hazardous
area
Non-hazardous
area
Safety retainer
Oxygen detector
Ｌｉ≒ 0
Ｃｉ≒ 0
≒ 0 shows a negligible value
Ｌｉ
Ｃｉ
Ｌｏ
Ｃｏ
Ｌｗ
Ｃｗ

6
(2) Non-explosion proof system
(3) Component inside detector head
Detector
head
Indicator/alarm unit
Non-hazardous area Non-hazardous area
CVVS 1.25mm2 2-core
or equivalent (MAX 2km)
4-20mA
Signal converter
Sensor lead wire
Terminal
4-20mA
Cable
Cable gland
O2
senso
r
Gas inlet
Gas outlet

7
4．HOW TO USE
４－１．Before using the detector head
All persons who use this detector for the first time and who has even used the detector are
requested to follow all the instructions for use carefully. If not, the instrument may be
defective and correct gas detection may not be performed.
４－２．Precautions for installation points
When installing this detector, note the following points.
Do not install the detector head and cable at the following points.
・Place to get direct rays of the sun.
・Places closed to high temperature and/or emission of electromagnetic wave.
・Place with vibration or shocks.
・Place where the mounting part is weak and it is easy to come out.
・Place where it is difficult to make maintenance and inspection.
・Place unable to secure grounding.
・Places where the temperature is drastically changed.
・Places exceeding operating temperature and humidity.
４－３．Maintenance space
A certain maintenance space must be secured around the detector head, so that the
maintenance staff can perform the safe and correct maintenance work. Pay due attention to
secure this space during work plan and execution.
WARNING

9
(2) In case of intrinsically safe system
You can build the intrinsically safe system by adding
optional zener barrier between detector head and indicator/alarm unit.
①Lead the applicable cable through cable inlet and connect to the terminal strip.
② Connect the optional zener barrier between this unit and indicator/alarm unit at
non-hazardous area. (See below fig.)
③ Connect the other side of the cable to the indicator/alarm unit side.
④ Connect the shield’s drain wire to ground on the indicator/alarm unit.
・ Do not alter, noｒ remodel the parts, etc.
・ Use the circuit breaker as for the power of indicator/alarm unit. Also it shall be mounted
nearby indicator/alarm unit and be specified that it is for power interruption of
indicator/alarm unit.
・ Ground the zener barrier separately corresponding to the A-class grounding with ground
resistance of 10Ω or less.
・ Use the specified cable.
・ For system installation, operation and maintenance, take care not to damage the intrinsically
safe design.
・ The power of the indicator/alarm unit shall be turned on after completion of all wirings. If
each wiring is carried out in the power on condition, short-circuit between terminals or an
electrical shock may be occurred.
* NOTE
When wiring, read the operating manual for the connected indicator/alarm unit.
WARNING
CAUTION
！
GD-F4A-SC-A
１
３
２ ４
D
e
te
c
t
o
r
h
e
a
d
I
n
d
i
c
a
t
o
r
/
a
l
a
r
m
u
n
i
t
Zener
barrier（MTL7728ac）
max. 2km
max. 250m(CVVS 1.25mm
2
)
Hazardous
zone
Non-hazardous
zone
Connection cable Connection
cable

10
４－８．Cautions at piping works
４－９．Example of piping connection
Gas inlet/outlet fitting of this unit is PT 1/8 female screw and provided with brass coupling.
Applicable piping is φ8 (O.D)-1t copper pipe. Secure the piping connections not to leak.
The piping material will be changed depending on corrosive gas contained in a sampled gas. In
such case, contact RIKEN KEIKI Co., Ltd.
(1) In case of pump suction
・ This unit is designed to sample the gas in an atmospheric pressure. Do not give an excessive
pressure to gas inlet and outlet of this unit.
・ Connect the exhaust pipe to the gas outlet located at the bottom of this unit and exhaust
the sampled gas to an area known to be non-hazardous.
WARNING
・ Use φ8 (O.D)-1t copper pipe and so on for piping.
・ Carry out piping works as straight as possible.
Excessively high load may cause burden on the suction pump, shortening the effective life of
the pump.
When bending the pipe, secure R (radius of curvature) enough to avoid loading to the piping.
・ Determine the suction side piping length while considering the response time. When the gas
is sampled from the piping end (gas detection point), the response time of the gas detection
sensor itself + delay time caused by the piping length becomes equivalent to the detector
response time.
・ Be sure to attach the gas suction port at the end of gas detection point.
・ Be sure to put dust filter in front of gas detector. If sampled gas contains water and
corrosive gases, removal device is required separately.
CAUTION
！
Detection
p
oint
GD-F4A-SC-A
Gas OUT
1.0±0.3L/min
Dust filter
Pump
Flow control
valve
P
Flowmeter

11
(2) In case of pressurized sample gas
(3) In case of aspirator suction
It is also possible to apply air aspirator unit to sample the gas by utilizing
instrumentation air. In this method, pressure to the sensor must be kept as
small as possible and make it to -20mmHg at a maximum.
As the load to oxygen sensor is high on this method, aspirator suction method
shall be used only when the pump cannot be used.
If the sample gas pressure would fluctuate, use the constant flow rate control
valve to keep the constant flow rate.
Exhaust the sampled gas to open air in principle. When make piping to exhaust
side necessarily, choose the piping diameter to keep the pressure loss due to
the length of piping within 10mmHg.
Dust filter
Detection
p
oint
GD-F4A-SC-A
Gas OUT
1.0±0.3 L/min
Flow control valve
Flowmeter
CAUTION
！
Flowmeter
Detection
p
oint Instrumentation air
Air consumption
：1-3Nℓ/min
pressure：1-35kg/cm2G
Dust filter
Flow control
valve
Aspirator
GD-F4A-SC-A

12
５．HOW TO OPERATE
５－１．Preparation for start up
Before making power on, take care of the following. If do not keep this, there is the danger
of electrical shock and damage of instrument.
５－２．How to start the detector head
① This detector head does not equip a power switch. Analog outputs of oxygen sensor
are converted to 4-20mA and transmitted to the indicator/alarm unit directory
through the connected cable. As far as the cable has been connected correctly, this
system starts operation by putting on the power switch in indicator/alarm unit.
② Let the gas flow be sampled to this unit by turning on the pump switch etc.
③ Adjust the flowrate to lead sampled gas to 1.0L±0.3mL/min.
④ Be sure to perform gas calibration at the time of new installation. Correct reading
may not be obtained before gas calibration.
５－３．How to exit
① Stop the sample gas supply to this unit by turning off the pump switch, etc.
② This system stops operation by putting off the power in indicator/alarm unit, since this
unit has no power switch.
・ Make protective grounding.
・ Check that the wiring with outer unit is made correctly.
・ Check that the supply voltage is within the rating.
・ Check that the rated fuse is used.
WARNING
・At the new installation, adjust the reading in indicator/alarm unit according to “6-2.
Calibration”.
CAUTION
！

13
６．MAINTENANCE
Gas detection and alarm instrument is kept in continuous operation over a long time and must
perform a vital role as a safety device. For this purpose, periodical inspection must be made.
The High-pressure Gas Safety Act in Japan sets forth the obligation of periodical inspection of
the gas detection and alarm instrument.
- Maintenance Contract –
Be sure to perform the regular maintenance since this is an instrument for security and
safety. If this detector head founds defective, contact RIKEN KEIKI immediately.
６－１．Maintenance intervals and items
The maintenance includes a daily maintenance which a person in charge of control and
operation of the gas detection instrument performs maintenance before work once a day, and a
monthly maintenance carried out once a month, and periodical maintenance conducted by the
service personnel designated by manufacturer. The maintenance items are confirmation of
lights, concentration indication and alarm function on the indicator/alarm unit side. It is also
necessary to carry out gas calibration at least every 6 months. The law in Japan sets forth that
the unit must issue an alarm during the circuit maintenance related to alarm while providing
normal operation, at least, once a month.
To maintain the safety operation of the gas detection instrument, it is recommended to keep
the maintenance contract with our authorized distributor for regular maintenance, adjustment
and overhaul etc including the gas sensitivity adjustment (gas calibration).
For the detail of maintenance contract, contact RIKEN KEIKI.
・This is a safety instrument and the maintenance every 6 months or more
is mandatory to ensure the safety. If the unit is used by continuously
without maintenance, the sensor sensitivity may change, resulting in
failure of correct detection.
WARNING
！
* NOTE
・Be sure to inform sections concerned beforehand when performing alarm test or
gas calibration. For the equipment connected with output signal from
indicator/alarm unit, perform them after disconnecting the output signal.
・Special trained engineer for gas detection instrument can perform maintenance
work accurately and efficiently.
・Then, it is recommended to contact RIKEN KEIKI for maintenance.

14
６－２．Calibration
Perform gas calibration at new installation, 6 months maintenance and sensor replacement.
６－２－１．Required kit and tools for calibration
Prepare following jigs and tools to perform zero and span adjustments.
Calibration gas (standard gas for zero and span)
Gas sampling bag for calibration gas
Gas sampling bag for exhaust gas.
Suction pump to lead calibration gas
Flowmeter with flow control valve (enable to control 1.0L/min)
Ammeter (For 4-20mA adjustment)
６－２－２．Performing a zero adjustment
①Plug the ammeter to terminal no 3(-) and 5(+) of terminal strip 2.
②Pack the zero gas (Nitrogen more than 99.9 vol %) into gas sampling bag.
③Disconnect piping for both gas inlet and gas outlet of this unit.
④Connect flowmeter （with flow control valve） and suction pump to the detector head.
Turn on the pump and adjust the reading of flowmeter to 1.0±0.3L/min.
⑤Connect gas sampling bag for calibration to the IN side of the pump and gas sampling
bag for exhaust gas to the outlet of this unit respectively.
⑥After reading by ammeter gets stable, adjust the reading to 4mA with ZERO
potentiometer.
⑦Stop the supply of zero gas, disconnect gas sampling bag for calibration and confirm
that the oxygen reading returns to 20.9vol %.
⑧Return disconnected piping to where they were (completion of zero adjustment).
６－２－３．Performing a span adjustment
① Plug the ammeter to terminal no 3(-) and 5(+) of terminal strip 2.
② Pack the span gas (fresh air for oxygen deficiency alarm instrument and their
concentration is around preset alarm level for other purpose) into gas sampling bag.
For simple calibration, you may be possible to use an ambient air as span gas
containing 20.9vol% O2 providing that the ambient pressure is 1 atm (1000±50hPa)
and contamination in air is negligible against span gas concentration.
③ Disconnect piping for both gas inlet and gas outlet of this unit.
④ Connect flow meter （with flow control valve） and suction pump to the detector head.
Turn on the pump and adjust the reading of flow meter to 1.0±0.3L/min.
⑤ Connect gas sampling bag for calibration to the IN side of the pump and gas sampling
bag for exhaust gas to the outlet of this unit respectively.
⑥ After reading by ammeter gets stable, adjust the reading to the equivalent current of
span gas concentration with SPAN potentiometer.
⑦ Stop the supply of span gas, disconnect gas sampling bag for calibration and confirm
that the oxygen reading by indicator/alarm unit is 20.9vol %.
⑧ Return disconnected piping to where they were (Completion of span adjustment).

15
６－３．Replacing the sensor
６－３－１．Replacement intervals of the sensor
To maintain the reliability of the measurement, it is recommendable to replace the sensor
periodically. Our oxygen sensor has an enough life span. However, the actual life is
depending on the operating conditions. Then, replace the sensor once a year as the
tentative deadline for the replacement cycle.
* NOTE
・Output current corresponding to gas concentration is a linear and
obtained by following equation.
Output current (mA) = 4 + 16 x
Oxygen concentration (vol%)
Full scale concentration (vol%)

17
６－４．Storage or treatment when not in use for a long period
Oxygen sensor is a kind of cell and will continue to consume its life even though it is not
used. When detector head is not used for a long period, take out the sensor from detector
head and store it at following environment to make lower the consumption of sensor.
・Environment of low temperature (5 - 10℃)
・Environment of low oxygen content
(Put a sensor into the container and seal off the container.)
６－５．List of recommendable spare parts for
regular replacement
No. Name of parts Inspection frequency Replacement interval Q’ty/unit
1 O-ring(sensor side in
the holder) 1 year 3-6 years 1
2 Packing(Housing side
in the holder) 1 year 3-6 years 1
* NOTE
・The replacement interval will change depending on operating condition and it does not
mean the warranty period.
Replacement interval changes according to the result of regular maintenance.