Detcon FP-700 - Manual (Page 15)

Model FP-700
FP-700 Instruction Manual Rev. 3.0 Page 11 of 40
NOTE: If the 4-20mA output is not being used, the Green wire from the sensor must be
connected to the Black wire at the (-) terminal on the Transient Protection Module to
ensure RS-485 communication is not disrupted by a 4-20mA Fault.
a) If applicable, terminate the RS-485 serial wiring as shown in Figure 11. Use the second plug (Out) as
termination point on the customer side to facilitate a continuous RS-485 serial loop
The RS-485 (if applicable) requires 24 gauge, two conductor, shielded, twisted pair cable between sensor and
host PC. General Cable Commodore part number ZO16P0022189 is recommended.
NOTE: Install a 120Ω resistor across A & B terminals on the last sensor in the serial loop.
c) Trim all exposed wire leads if they are not permanently landed in the terminal block.
d) Replace the junction box cover.
2.7 Initial Start Up
Upon completion of all mechanical mounting and termination of all field wiring, apply system power in the
range of 11.5-30VDC (24VDC typical) and observe the following normal conditions:
a) FP-700 display reads “0”, and no fault messages are flashing.
b) A temporary upscale reading may occur as the sensor heats up. This upscale reading will decrease to
0ppm within 1-2 minutes of power-up, assuming there is no combustible gas in the area of the sensor.
NOTE: The 4-20mA signal is held constant at 4mA for the first two minutes after power up.
Initial Operational Tests
After a warm up period of 1 hour, the sensor should be checked to verify sensitivity to combustible gas.
Material Requirements
 Detcon PN 613-120000-700 700 Series Splash Guard with integral Cal Port -OR-
 Detcon PN 943-000006-132 Threaded Calibration Adapter
 Detcon PN 942-520124-050 Span Gas; 50% LEL methane/balance Air at fixed flow rate of 200-
500cc/min (use with 0-100% LEL range).
 Detcon PN 942-520124-025 Span Gas; 25% LEL methane/balance Air at fixed flow rate of 200-
500cc/min (use with 0-50% LEL range).
NOTE: Do not use calibration gases in Nitrogen background gas mixtures. This will cause
significant reading inaccuracies.
a) Attach the calibration adapter to the threaded sensor housing. Apply the test gas at a controlled flow rate
of 200 - 500cc/min (200cc/min is the recommended flow). Allow 1-2 minutes for the reading to stabilize.
Observe that during the 1-2 minutes the ITM display increases to a level near that of the applied
calibration gas value.
b) Remove test gas and observe that the ITM display decreases to “0”.