Rockwell Automation 1756-OF8H ControlLogix HART Analog I/O Modules User Manual
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Rockwell Automation Publication 1756-UM533C-EN-P - February 2011
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Module Troubleshooting Chapter 11
When troubleshooting, consider these more obscure problems.
• The same device appears to be connected to every channel because a wiring
problem causes signals to get connected across channels. In some cases,
loose IRET wires cause the path to ground to flow through other channels.
• If Keep HART Replies for XX seconds is set small – less than 5 seconds -
the module throws away replies before you get a chance to retrieve them.
This affects both MSG pass-through messages and PC-based asset
management, such as FieldCare software. We recommend 15 seconds for
this parameter.
• Be sure you have a HART device. Foundation Fieldbus, Profibus PA, and
plain 4…20 devices look the same on the outside and power up OK.
• Write protect jumper is not reported correctly. This gets refreshed only if
the device reports it changed. E&H and Rosemount devices don’t.
Un-enable HART then re-enable HART to get it refreshed on the HART
Device Info dialog.
For pass-through message troubleshooting issues, use these tips:
• Check module-specific online help.
• Copy the Handle to the Query.
• Check sizes of MSG and HART command.
• Check packing, alignment, and byte ordering.
• Use MsgReady.
• Name tags and UDTs similarly to group them together for convenience.
For example, start the related tags with the same prefix.
• Check .ER and Status.
For input tag troubleshooting, use these tips:
• Local:7:I.Ch0Fault – if 1, suspect wiring/instrument problem.
• Local:7:I.Ch0HARTFault – if 1, check Local:7:C.HARTEn (Enable
HART).
• Local:7:I.HART.Ch0DeviceStatus.Init – HART is enabled, but still
trying to get a response from device.
• Local:7:I.HART.Ch0DeviceStatus.Fail – HART is disabled, or
not responding.
• Local:7:I.HART.Ch0DeviceStatus.CurrentFault – the mA current
measured doesn’t match what is reported via HART. Could be caused by a
recent change in value. This is intended to indicate a current leak, such as
water in the conduit.
• Local:7:I.HART.Ch0DeviceStatus.ResponseCode – if negative, there is
some communication problem. If positive, device is indicating some
problem with the command. 16#40 means command not supported.
• Local:7:I.HART.Ch0DeviceStatus.FieldDeviceStatus – 0 is good; refer to
Help or see the
for more information.