If noise and/or offsets disappear, the interference was coming into the transmitter
through one of the sensor wires. You can operate the system permanently with
simplified wiring.
4. Check for extra ground connections or induced noise. To avoid induced noise in the
sensor cable, run it as far away as possible from power cables, relays, and electric
motors. If ground loop problems persist, consult the factory.
An experienced service technician may need to solve the problem.
9.6.6 pH readings are moderately noisy and tend to wander.
pH readings that are moderately noisy (±0.1 pH) and tend to wander are probably caused
by bubbles getting trapped against the pH sensor.
Although the overflow sampler is designed to allow bubbles to escape before they reach
the pH sensor, and the sensor itself is designed so trapped air bubbles don't interfere with
the measurement, bubbles may occasionally be a problem. Shaking the sensor will
dislodge the bubbles. If bubbles remain a problem, contact the factory.
9.7 Troubleshooting when no error message is
showing - general
Problem See Section
New temperature during calibration more than 2-3 °C
different from the live reading.
Difference between transmitter and standard
thermometer is greater than 3 °C.
Current output is too low. Current output too low
Alarm relays do not operate when setpoint is exceeded. Alarm relays don't work.
9.7.1 Difference between transmitter and standard
thermometer is greater than 3 °C.
Recommended actions
1. Make sure the reference thermometer, resistance temperature device, or
thermistor is accurate.
General purpose liquid-in-glass thermomemters, particularly ones that have been
mistreated, can have surprisingly large errors.
2. Make sure the temperature element in the pH sensor is completely submerged in
the test liquid.
3. Make sure the standard temperature sensor is sumberged to the correct level.
4. Review Calibrate temperature.
9.7.2
Current output too low
Load resistance is too high. Maximum load is 550 Ω.
Reference Manual Troubleshoot
00809-0100-3412 May 2019
Rosemount FCL 1056 101
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