Chapter 6 Troubleshooting; Overview; Troubleshooting For 4-20 Ma Output - Emerson Rosemount 2051 Reference Manual

Reference Manual
00809-0100-4107
6 Troubleshooting
6.1

Overview

The following sections provide summarized maintenance and troubleshooting suggestions
for the most common operating problems.
6.2

Troubleshooting for 4-20 mA output

6.2.1 Transmitter milliamp reading is zero
Recommended actions
6.2.2 Transmitter not communicating with communication
device
Recommended actions
6.2.3 Transmitter milliamp reading is low or high
Recommended actions
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1. Verify terminal voltage is 10.5 to 42.4 Vdc at signal terminals.
2. Check power wires for reversed polarity.
3. Check that power wires are connected to signal terminals.
4. Check for open diode across test terminal.
1. Verify terminal voltage is 10.5 to 42.2 Vdc.
2. Check loop resistance.
(Power supply voltage - terminal voltage)/loop current should be 250 Ω
minimum.
3. Check that power wires are connected to signal terminals and not test
terminals.
4. Verify clean DC power to transmitter.
Maximum AC noise is 0.2 volts peak to peak.
5. Verify the output is between 4 and 20 mA or saturation levels.
6. Use the communication device to poll for all addresses.
1. Verify applied pressure.
2. Verify 4 and 20 mA range points.
3. Verify output is not in alarm condition.
4. Perform analog trim.
5. Check that power wires are connected to the correct signal terminals (positive to
positive, negative to negative) and not the test terminal.
Troubleshooting
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