Troubleshooting
10.13
Check HART communication loop
Prerequisites
You will need the following:
• A copy of your transmitter installation manual
• A Field Communicator
• Optional: the
HART Application Guide
, available at
www.hartcomm.org
Procedure
1.
Verify that the loop wires are connected as shown in the wiring diagrams in the transmitter
installation manual.
If your HART network is more complex than the wiring diagrams in the transmitter installation
manual, contact either Micro Motion or the HART Communication Foundation.
2.
Disconnect the primary mA output wiring from the transmitter.
3.
Install a 250 Ω resistor across the transmitter’s primary mA output terminals.
4.
Check the voltage drop across the resistor (4–20 mA = 1–5 VDC).
If voltage drop is less than 1 VDC, add resistance to achieve a voltage drop of greater than 1 VDC.
5.
Connect a Field Communicator directly across the resistor and attempt to communicate (poll).
If communication with the transmitter cannot be established, the transmitter may need service.
Contact Micro Motion.
10.14
Check
HART Address
and
Loop Current Mode
The default
HART Address
is 0. This address is appropriate unless the transmitter is in a multidrop
environment. If the
HART Address
is configured to a value other than 0, some configuration tools will
automatically change
Loop Current Mode
as well.
If
Loop Current Mode
is
Disabled
, the primary mA output will not report process variable data or indicate
fault conditions.
192
Micro Motion 9739 MVD Transmitters
