Detcon PI-700 0-500ppb - Manual (Page 42)

Model PI-700 0-500ppb
PI-700 0-500ppb Instruction Manual Rev. 0.0 Page 38 of 53
Unreadable Display
If due to excessive sunlight, install a sunshade to reduce glare.
Nothing Displayed – Transmitter not Responding
Verify condulet has no accumulated water or abnormal corrosion.
Verify required DC power is applied to correct terminals.
Swap with a known-good ITM to determine if ITM is faulty.
Faulty 4-20 mA Output
If Sensor has a normal reading with no Faults displayed, and the 4-20 mA signal output is 0mA….
Check that wiring is properly connected at terminal blocks and through to controller inputs.
The 4-20 output loop must be closed (resistance of < 1000 ohms) to avoid the Loop Fault.
Perform a “Signal Output Check” sequence via Section 3.5.7 and verify 4-20mA output with Current Meter.
Swap with new ITM to determine if the ITM’s 4-20mA output circuit is faulty.
No Communication - RS-485 Modbus™
If sensor has a normal reading with no Faults displayed and the Modbus™ is not communicating….
Verify that the correct (and non-duplicated) serial address is entered (per Section 3.5.3).
Check that the wiring is properly connected at terminal blocks, and the serial loop is wired correctly.
Perform a “Signal Output Check” per Section 3.5.7 and troubleshoot wiring.
Consider adding a Modbus™ repeater if the distance from the nearest distribution drop is excessive.
Swap with new ITM to determine if the ITM’s serial output circuit is faulty.
Refer to Detcon’s “Guide to Proper Modbus™ Communications” Application Note.