Det-Tronics 505 Combustible Gas Detector Transmitter with Combustible Gas Sensor CGS - Manual (Page 12)

9 95-8472 3.1
REPLACING AN EXISTING K SERIES OR MODEL
500 TRANSMITTER WITH A MODEL 505
1. Remove power from the existing K Series or Model
500 Transmitter, then remove the junction box
cover.
2. Remove the transmitter module from the junction box.
Do not remove the connector board at this time.
3. Unplug the sensor from the connector board. If the
sensor is installed separately from the transmitter
junction box, disconnect the three wires from the
sensor terminal strip. Note the location of the sensor
cable shield drain wire (if used). It will be reconnected
in the same manner later.
4. Disconnect the three wires from the power and signal
terminal strip. Note the location of the shield drain
wire (if used). It will be reconnected in the same
manner later.
5. Remove the two screws, then remove the connector
board from the junction box.
6. Install the new Model 505 transmitter board in the
junction box. The mounting hole pattern of the
transmitter board should match the holes in the
existing junction box. Use standoffs if necessary
to increase the clearance between the transmitter
board and the bottom of the junction box. If a
ground lug was used, re-install it at the transmitter
board mounting hole with the exposed foil to ensure
electrical continuity.
7. Remove the plug-in connector for the power and
signal wiring from Model 505 transmitter board, and
connect the existing power supply and signal wires
at the proper locations on the connector. The proper
locations are identified on the Model 505 transmitter
board by “+ (plus), – (minus) and sig (signal)”
markings.
8. Insert the plug-in connector into the power and
signal wire receptacle on the Model 505 transmitter
board. Reconnect the power and signal cable
shield drain wire (if used) as previously installed.
Route any excess power and signal wiring inside
the junction box around the perimeter of the Model
505 transmitter board to allow easy access to the
switches and potentiometers.
9. Connect the sensor plug onto the male sensor
terminal. If the sensor is installed separately from the
transmitter junction box, connect the three sensor
wires to the sensor wiring plug-in connector. The
proper sensor wire locations are identified on the
Model 505 transmitter board by “red, wht and blk”
markings. Note the location of the sensor cable
shield drain wire (if used) and ensure that it is re-
connected as in the original wiring configuration.
10. Route the sensor wires inside the junction box around
the perimeter of the transmitter board to allow easy
access to the switches and potentiometers.
11. Apply power to the transmitter and perform “Startup
Procedure,” “Sensor Voltage Adjustment” and
“Calibration” as described in this manual.
12. Replace the junction box cover when complete.
STARTUP PROCEDURE
1. Output loads that are normally actuated by the
system should be secured (remove power from all
output devices) to prevent undesired activation of
these devices.
NOTE
Prior to calibration, it is possible for the transmitter
to generate a spurious signal output up to 20 mA
when power is first applied.
2. Double check all internal and external wiring for
proper connections. Check sensor operating voltage
if sensor separation is utilized.
3. If a controller is used, set the alarm setpoints for the
desired levels. (Refer to the controller instruction
manual.)
4. Apply power to the Model 505. Allow the transmitter/
sensor to stabilize for two hours minimum
before calibration for maximum accuracy and
repeatability.
NOTE
When power is applied to the Model 505, it enters
a 15 second time delay before beginning normal
operation. This power-up time delay allows time for
the sensor to stabilize before the signal output is
generated.
ZERO ADJUST
SPAN ADJUST
TEST POINTS
ZERO/SPAN SWITCH
SENSOR VOLTAGE ADJUST
CAL/NORM SWITCH
CALIBRATE LED
4 MA ADJUST
B1944
Figure 8—Location of Switches and Potentiometers
on Transmitter Circuit Board