Cable Recommendation - Honeywell EC-FX-NH3 Instruction And Installation Manual

• RS-485: MODBUS RTU communication protocol.

Cable Recommendation:

• 4/20 mA output: Use #18/3 shielded cable (Belden #8770 or
equivalent). Length of cable to sensor should be no greater than
1,500 feet.
RS-485 output: For communication cable, use 24 AWG twisted pair,
•
shielded (Belden #9841 or equal), cable runs up to 2,000 feet. Avoid
"T-taps" if possible. Do not exceed 65 feet per T-tap. Do not exceed
130 feet total of all T-taps (per channel). For power cable, use 14
AWG (Belden #5100UE or equal), cable runs up to 1,000 feet, for
each power supply. Larger power cable and/or additional power
supplies may be required for longer cable runs and/or increased
number of sensors. Due to variables such as sensor current draw,
line loss, and cable size, contact Honeywell Analytics for help with
power cable requirements.
Monitoring: The EC-FX-NH3 ammonia detector may be monitored by the GM-
JR, AirAlert 96d, or other appropriately configured system. For 4/20 output,
TM
monitoring equipment must be configured to indicate a fault if the signal is
below 1.5 mA. All signals over 20 mA must be considered a high gas
concentration, not a fault condition.
NOTE for PLC applications: The signal output load can range
from 0 to 700 ohms, where the maximum load resistor at a 24 VDC
supply is 700 ohms and the maximum load resistor at a 10 VDC
supply is 267 ohms. Any load outside these values will indicate a
fast flash on the red LED while in operation or this test mode during
normal operation. The error LED will blink fast at any time if the
signal output cannot source the necessary current.
OPERATOR MANUAL
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