Transmitter problems

The below list provides the list of general pressure transmitter problems and their possible corrective actions.

Transmitter milliamp reading is zero

Verify power is applied to signal terminals
Check power wires for reversed polarity
Verify terminal voltage is 10.5 to 42.4 Vdc
Check for open diode across test terminal
Transmitter Not Communicating with Field Communicator

Verify the output is between 4 and 20 mA or saturation levels
Verify terminal voltage is 10.5 to 42.4 Vdc
Verify clean DC Power to transmitter (Max AC noise 0.2 volts peak to peak)
Check loop resistance, 250 ohms minimum (Power supply voltage -transmitter voltage/loop current)
Have Field Communicator poll for all addresses
Transmitter milliamp reading is low or high

Verify applied pressure
Verify 4 and 20 mA range points
Verify output is not in alarm condition (Alarm option available in some transmitters)
Verify if 4 – 20 mA output trim is required
Transmitter will not respond to changes in applied pressure

Check test equipment
Check impulse piping or manifold for blockage
Verify the transmitter is not in multidrop mode
Verify applied pressure is between the 4 and 20 mA set points
Verify output is not in alarm condition
Verify transmitter is not in Loop Test mode
Digital Pressure Variable reading is low or high

Check test equipment (verify accuracy)
Check impulse piping for blockage or low fill in wet leg
Verify transmitter is calibrated properly
Verify pressure calculations for application
Digital Pressure Variable reading is erratic

Check application for faulty equipment in pressure line
Verify transmitter is not reacting directly to equipment turning on/off
Verify damping is set properly for application
Milliamp reading is erratic

Verify power source to transmitter has adequate voltage and current
Check for external electrical interference
Verify transmitter is properly grounded
Verify shield for twisted pair is only grounded at one end

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