Technical
Gas Type
Oxygen
Input Voltage
12~30v DC – 24v nominal
Optional Mains 230/115vAC 50/60hz
Nominal 30mA – 120mA full alarm
Output Standard
Analogue 4~20 mA (250 ohms max) – sink/source
(source mode – standard)
Option 1~5v output – solder G
CV–Sensor Cable
3 core screened
Alarm Relay
Main relay S.P.C.O. 3A/230v AC
Fire Alarm panel signalling – cut F
Trip Indicator LED – trip point selectable 10% to full scale
(Auto reset)
On board sounder
Auxiliary output DC volts – standard–as input volts 24v
DPM – gas readout display – (zero and span potentiometers used
only for DPM setting)
SET UP PROCEDURE
Installation
Siting of the equipment should be chosen with regard to the
following points:
1. Safe area use only (not hazardous zone)
2. Away from sources of heat and with room for adequate air
circulation.
3. Within easy reach for operating and maintenance personnel.
4. Connecting cables to be electrically shielded.
5. For further information regarding sensor location see our website
www.gds–technologies.co.uk.
Note: Sensor cables should not be run in the same ducting as power
cables.
Removing Lid (30J)
Using a 2.5mm Allan key withdraw the two lid screws until they clear
the lid bezels. Push the lid up until it is stopped by the circuit board
located inside the enclosure; pull one side to remove the lid.
Mounting
Direct wall mount – use M4 or No.8 screws through the membrane
of the 4 stand–offs. Where the stand–offs are to be removed (rotate
each stand–off using pliers) drill at mounting points marked C or
utilise knock out slots.
For surface mount box drill at points B (2 off)
For conduit box fixing drill at points A (2 off)
Supply Input
Ensure that the supply is correct for the voltage rating of the
indicator. Ensure that the supply is OFF before making any
connections and wire only in accordance with the terminal detail.
Calibration (factory set)
1. Connect a digital voltmeter (miIIivolt range) to the X and Y test
terminals, the CV is preset in the current source mode.
2. Remove the sensor terminal connector from the PCB J4 or yellow
wire and adjust the 4mA potentiometer for 4mA (4mV).
3. Where a digital panel meter is fitted to the CV card the reading
may be adjusted by the DPM Zero potentiometer.
Reconnect the cell and allow reading to stabilise adjust the DVM
reading to 17.3mV (20.8% ambient oxygen) using the 20mA
potentiometer.
Where a Digital panel meter is fitted the display may be adjusted by
using the DPM S potentiometer (span).
Alarm Trip Point Adjustment (factory set)
This level will normally be set at 23% for oxygen.
1. Connect the DVM as above, using the 20mA potentiometer adjust
for the required trip level (OM DPM).
2. Adjust the alarm level potentiometer until the alarm LED just
comes on.
3. Using the 20mA potentiometer re–adjust the DVM to 17.3mV.
The above adjustment may be carried out in house by connecting
the CV transmitter directly to a DC power supply and connecting a
100Ω load resistor. See diagrams on left.
Should a full board be required to operate on a 2 wire 4-20mA loop
then the alarm relay / LED must be disabled – remove JP2.
A
B
C
D
X
P
-
-
+
-
+
+
Y W
P Y W
SENSOR
FIELD TERMINALS
TO GDS
ALARM PANEL
PCN149
E
Y
20mA
4mA
TP2 TP4
TP1
RV3
JP1
RV4
TP3
W Y P
No C Nc
NC
C
NO
- +
Sensor Terminal
Sounder Mute
Sounder
FULL CV BOARD
T
RELAY
BOARD
CV
TRANSMITTER
EOL
Output Signal
Adjust
Test Points
Alarm Level
Adjust
Alarm
LED
JP2
20mA
4m
A
Span
Zero
DP
M
E
A
JP1
-
+
W Y R
- +
J4
JP3
JP4
X
Y
B
C
D
W+
Y
SIG
P -
Field Terminals
to GDS Alarm Unit
U5
LK1
A L
SAFE AREA BOARD
EExd BOARD
-
+
-
+
E
SIG
-
+
-
+
E
SIG
JP1 Jumpers BD
JP1 Jumpers AC
3 Wire Sink
100Ω load
100Ω load
3 Wire Source
2 Wire
24vDC
24v DC
Output
W Y P
No C Nc
NC
C
NO
-
+
+
Sensor
Terminal
Sounder
RELAY
BOARD
Sensor
Terminal
EOL
Output Signal
Adjust
Test Points
Alarm Level
Adjust
Alarm
LED
JP2
20m
A
4m
A
Span
Zero
DP
M
E
A
JP1
-
+
W Y R
- +
J4
JP3
JP4
X
Y
B
C
D
W+
Y
SIG
P -
Field Terminals
to GDS Alarm Unit
U5
LK1
A L
T
1A
Relay
RL2
3A
Relay
RL1
-
24v DC
Output
+
-
