Meriam MFC5150 HART Communicator Manual User Manual

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The user now has the option of making further modifications to the parameters on the HART

menu, or

committing them to the device.

4.7 Communication Troubleshooting

If a HART

device is connected to the unit but “No Devices Found” notification is received, or the device is

not in the table of found devices:

1) Make sure all connections are correct and secure. Check for shorts, open circuits and multiple
grounds.
2) Determine if the loop resistance is greater than 250Ω and less than 1100Ωs. If less than 250 Ω

then use the supplied 250 Ω load resistor in series with the loop (see diagram HART

Connections

section).
3) Determine if any device is in burst mode. Disable burst mode if possible during troubleshooting.
4) Check the polling address type and range selected from the system menus. If the polling address
set on the transmitter is outside of the range selected for the communicator, the device will not be
discovered. Set the poll type to “by address” and set the polling address range to the maximum (0-
15 for HART

Universal Revision

5 devices, 0-63 for newer HART

devices). Start a new poll

and determine if the device is found.
5) If multiple HART

devices are in the loop, there could be an address conflict (two devices at

same address). Testing the devices individually is the best path.
6) Determine if there are multiple master devices on the loop. HART

communication only permits

one primary and one secondary master. Remove all other master devices from the loop for
troubleshooting.

When the message “Generic” is displayed after connecting to a HART

device there are two possible causes:

1) No device specific DD for that device is currently installed in communicator memory. This

could occur if the device DD has not been released by the HART Communication Foundation
(visit their website for full list), or if the DD database on your PC requires updates. See Secion 5
for update instructions.

2) The connected HART

device supports only HART

Universal and Common Practice

commands (i.e. generic commands). There are several such devices on the market, particularly
level type devices.

If multiple devices of the same name appear at different addresses, the cause is normally a HART

Universal Revision 5 device in the loop and the polling range selected on the communicator extending
beyond HART

polling address 15. Addresses beyond 15 were undefined until HART

Universal

Revision 6.