SMAR LD290, Operation And Maintance Manual

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Section 4
4.1
MAINTENANCE PROCEDURES
General
NOTE
Equipments installed in hazardous atmospheres must be inspected in compliance with the IEC60079-
17 standard.
SMAR
LD290 pressure transmitters are extensively tested and inspected before delivery to the end
user. Nevertheless, its design includes additional information for diagnosis purposes, in order to provide
an easier fault detection capability and, as a consequence, an easier maintenance.
In general, it is recommended that end users do not try to repair printed circuit boards. Spare circuit
boards may be ordered from SMAR whenever necessary.
The sensor has been designed to operate for many years without malfunctions. Should the process
application require periodic cleaning of the transmitter, the flanges may be easily removed and
reinstalled.
Should the sensor eventually require maintenance, it may not be changed in the field. In this case, the
possibly damaged sensor should be returned to SMAR for evaluation and, if necessary, repair. Refer to
the item "Returning Materials" at the end of this Section.
Diagnostic by Display
Symptom: NO LINE CURRENT
Probable Source of Trouble :
✓
Transmitter Connections
•
Check wiring polarity and continuity.
•
Check for shorts or ground loops.
•
Check if the power supply connector is connected to main board.
✓
Power Supply
•
Check power supply output. The voltage must be between 12 and 45 Vdc at transmitter
terminals.
✓
Electronic Circuit Failure
•
Check the main board for defect by using a spare one.
Symptom: CURRENT OF 21.0 mA or 3.6 mA
Probable Source of Trouble :
✓
Pressure Tap (Piping)
•
Verify if blocking valves are fully open.
•
Check for gas in liquid lines or for liquid in dry lines.
•
Check the pressure connection.
•
Check if pressure applied is not over upper limit of transmitter's range.
Sensor to Main Circuit Connection
✓
Electronic Circuit Failure
•
Check the sensor circuit for damage by replacing it with a spare one.
•
Replace sensor.
Symptom: INCORRECT OUTPUT
Probable Source of Trouble :
✓
Transmitter Connections
•
Check power supply voltage.
•
Check for intermittent short circuits, open circuits and grounding problems.