133
Reference Manual
00809-0100-4021, Rev GC
Section 3: HART commissioning
April 2014
HART® commissioning
3.15.6 Scaled output trim
The Scaled D/A Trim command matches the 4 and 20 mA points to a user-selectable reference
scale other than 4 and 20 mA (2–10 volts, for example). To perform a scaled D/A trim, connect
an accurate reference meter to the transmitter and trim the output signal to scale as outlined in
the Output trim procedure.
3.16 Troubleshooting
3.16.1 Overview
If a malfunction is suspected despite the absence of a diagnostics message on the field
communicator display, follow the procedures described in Table 3-2 to verify that transmitter
hardware and process connections are in good working order. Under each of four major
symptoms, specific suggestions are offered for solving problems. Always deal with the most
likely and easiest-to-check conditions first.
Advanced troubleshooting information for use with field communicators is available in Table 3-3
on page 134.
HART 5 Fast Keys
3, 4, 5, 2
HART 7 Fast Keys
3, 4, 5, 2
Table 3-2. HART / 4–20 mA Basic Troubleshooting
Symptom Potential source Corrective action
Transmitter Does Not
Communicate with Field
Communicator
Loop Wiring
• Check the revision level of the transmitter device descriptors (DDs) stored
in your communicator. The communicator should report Dev v4, DD v1
(improved), or reference “Field communicator” on page 30 for previous
versions. Contact Emerson Process Management Customer Central for
assistance.
• Check for a minimum of 250 ohms resistance between the power supply
and Field Communicator connection.
• Check for adequate voltage to the transmitter. If a Field Communicator is
connected and 250 ohms resistance is properly in the loop, then the
transmitter requires a minimum of 12.0 V at the terminals to operate (over
entire 3.5 to 23.0 mA operating range), and 12.5 V minimum to
communicate digitally.
• Check for intermittent shorts, open circuits, and multiple grounds.
High Output
Sensor Input
Failure or
Connection
• Connect a Field Communicator and enter the transmitter test mode to
isolate a sensor failure.
• Check for a sensor open circuit.
• Check if the process variable is out of range.
Loop Wiring
• Check for dirty or defective terminals, interconnecting pins, or receptacles.
Power Supply
• Check the output voltage of the power supply at the transmitter terminals.
It should be 12.0 to 42.4 Vdc (over entire 3.5 to 23.0 mA operating range).
Electronics Module
• Connect a Field Communicator and enter the transmitter test mode to
isolate module failure.
• Connect a Field Communicator and check the sensor limits to ensure
calibration adjustments are within the sensor range.
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