Rockwell Automation 1756-OF8H ControlLogix HART Analog I/O Modules - Manual (Page 77)

Rockwell Automation Publication 1756-UM533C-EN-P - February 2011 77
1756-IF16H HART Analog Input Module Chapter 5
1756-IF16H Module Fault Word Bits
Bits in this word provide the highest level of fault detection. A nonzero condition
in this word reveals that a fault exists on the module. You can examine further to
isolate the fault.
Table 13 lists tags that can be examined in ladder logic to
indicate when a fault has occurred.
1756-IF16H Channel Fault Tags
During normal module operation, bits in the Channel Fault word are set if any of
the respective channels has an Under or Overrange condition. Checking this
word for a nonzero value is a quick way to check for Under or Overrange
conditions on the module.
Channel Fault bits for all channels are also set (16#FFFF) if calibration is being
performed or a communication fault has occurred between the module and its
owner controller.
1756-IF16H Channel Status Tags
Table 14 describes the channel status tags.
Specifications and
Certifications See the 1756 ControlLogix I/O Modules Specifications Technical Data,
publication
1756-TD002 , for specific module specifications and certifications.
Table 13 - Tags That Can Be Examined in Ladder Logic
Tag Description
Analog Group Fault This bit is set when any bits in the Channel Fault word are set. Its tag name is AnalogGroupFault.
Calibration Fault This bit is set when any of the individual Channel Calibration Fault bits are set. Its tag name is CalFault.
Table 14 - Tags That Show Channel Status
(1)
Tag Bit Description
ChxCalFault 7 This bit is set if an error occurs during calibration for Channel x, causing a bad calibration. Also sets CalFault in the
Module Faults.
ChxUnderrange 6 This bit is set when the analog signal is less than or equal to the minimum detectable signal. Because the signal cannot
be measured, it may be significantly below the minimum value. Also sets ChxxFault in the Channel Faults.
ChxOverrange 5 This bit is set when the analog signal is greater than or equal to the maximum detectable signal. Because the signal
cannot be measured, it may be significantly above the maximum value. Also sets ChxxFault in the Channel Faults.
(1) Bits 0…4 are not used.