Hydronix Hydro-Probe - Chapter 5 Sensor Diagnostics; Sensor Diagnostics

Configuration and Calibration Guide HD0679 Rev 1.2.0 43
Chapter 5 Sensor Diagnostics
The following tables list the most common faults found when using the sensor. If you are unable to
diagnose the problem from this information, please contact Hydronix technical support.
1 Sensor Diagnostics
1.1 Symptom: No output from Sensor
Possible
explanation
Check
Required result
Action required on
failure
Output is working
but not correctly
Perform simple test
with hand on sensor
Milliamp reading
within the normal
range (0-20mA, 4-
20mA)
Power down and re-
power sensor
No power to sensor
DC power at
junction box
+15Vdc to +30Vdc
Locate fault in
power supply/wiring
Sensor has
temporarily locked
up
Power down and re-
power sensor
Sensor functions
correctly
Check power
No sensor output at
control system
Measure sensor
output current at
control system
Milliamp reading
within the normal
range (0-20mA, 4-
20mA). Varies with
moisture content
Check cabling back
to junction box
No sensor output at
junction box
Measure sensor
output current at
terminals in junction
box
Milliamp reading
within the normal
range (0-20mA, 4-
20mA). Varies with
moisture content
Check sensor
connector pins
Sensor MIL-Spec
connector pins are
damaged
Disconnect the
sensor cable and
check if any pins
are damaged
Pins are bent and
can be bent to
normal to make
electrical contact
Check sensor
configuration by
connecting to a PC
Internal failure or
incorrect
configuration
Connect the sensor
to a PC using the
Hydro-Com
software and a
suitable RS485
converter
Digital RS485
connection is
working. Correct the
configuration
Digital RS485
connection is not
working. Sensor
should be returned
to Hydronix for
repair.