Technical Bulletin - SL/SX Level Sensor Troubleshooting

UNIT: Model SL and SX Liquid Level Transmitter

Revision: 1.0 | Doc #: TS-3001

Symptoms, and their associatd corrective actions have been provided for the purpose of field troubleshooting the SL/SX Liquid Level Transmitters.

Note: As many sensors provide feedback to cooling systems, agitator controls or lockout controls be sure to properly secure all associated systems prior to performing troubleshooting.

NO CURRENT OUTPUT
  • Loop may be broken - Measure voltage across LOOP(+) and LOOP(-) screws. Result should be between 12-40 VDC.
  • Sensor circuitry damaged - Move LOOP(+) wire to TEST(-) screw. If output loop now works, internal sensor circuit has been damaged. Contact Anderson.
OUTPUT CURRENT STUCK BETWEEN 4 AND 20 mA
  • Sensor must be in RUN mode - be sure sensor is NOT in CURRENT CAL or FIELD CAL switch positions.
  • Check diaphragm for damage - dent or ding may cause output shifts beyond adjustment. Contact Anderson.
  • Verify that CURRENT CAL value is correct - Section 3.3 of Service Manual.
CANNOT SET TO 4.00 mA (+/- .04 mA) USING ZERO SWITCH
  • Verify that CURRENT CAL value is correct - Section 3.3 of Service Manual.
  • If current value is greater than 4.00 mA, sensor is damaged. Contact Anderson.
  • If current is less than 4.00 mA, follow checks in "No Current Output" section above.
SENSOR OUTPUT SIGNAL NOT STABLE - DRIFTS
  • Verify that CURRENT CAL value is correct - Section 3.3 of Service Manual.
  • Check diaphragm for damage - dent or ding may cause output shifts beyond adjustment. Contact Anderson.
  • Check for signs of moisture / water in housing. If found, check cable entry. Must be sealed to prevent moisture entry. Cap must be tightened completely to engage gasket. Removing sensor from service - place in low humidity area with cap removed. Sensor may function correctly when dry.
  • Prior to rezero, vessel must be empty and temperature stable. Recommend rezero after process and prior to CIP.
CURRENT OUTPUT VALUE INCORRECT
  • Follow section 3.3 of Service Manual - Verifying Sensor Calibration. Sensor may have been adjusted improperly with product in vessel.
  • If calibration does not match factory setting, calibrate as shown in Section 3.5 of Service Manual.
OUTPUT CURRENT JUMPS TO VALUE GREATER THAN 23 mA
  • Follow section 3.3 of Service Manual - Verifying Sensor Calibration. Sensor may have been adjusted improperly with product in vessel.
  • If calibration does not match factory setting, calibrate as shown in Section 3.5 of Service Manual.