Pressure Transmitter Troubleshooting Tips

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

Reference : Rosemount