Rockwell Automation 1756-OF8H ControlLogix HART Analog I/O Modules - Manual (Page 88)

88 Rockwell Automation Publication 1756-UM533C-EN-P - February 2011
Chapter 6 1756-OF8H HART Analog Output Module
Channel Status Tags
Any of the channel status words (eight words for 1756-OF8H modules), one for
each channel, display a nonzero condition if that particular channel has faulted.
Some of these bits set bits in other Fault words.
When the High or Low Limit Alarm bits (ChxHLimitAlarm or ChxLLimit
Alarm) in any of the words are set, the appropriate bit is set in the Channel Fault
word.
When the Calibration Fault bit (CalFault) is set in any of the words, the
Calibration Fault bit (bit 11) is set in the Module Fault word.
Table 19 lists the
conditions that set each of the word bits.
Specifications and
Certifications See the 1756 ControlLogix I/O Modules Specifications Technical Data,
publication
1756-TD002 , for specific module specifications and certifications.
Table 19 - Conditions That Set Each of the Word Bits
(1)
Tag (status words) Bit Event That Sets This Tag
ChxOpenWire
Chx.DeviceStatus.OpenWire 7 This bit is set only if the configured Output Range is 0…20 or 4…20 mA and the circuit becomes open
due to a wire falling off or being cut when the output being driven is above 0.1 mA. The bit remains set
until correct wiring is restored.
ChxNotaNumber
(2)
Chx.DeviceStatus.NotANumber
5 This bit is set when the output value received from the controller is NotANumber (the IEEE NaN value).
The output channel holds its last state.
ChxCalFault
Chx.DeviceStatus.CalFault 4 This bit is set when an error occurred when calibrating. This bit also sets the appropriate bit in the
Channel Fault word.
ChxInHold
(2)
Chx.DeviceStatus.InHold
3 This bit is set when the output channel is currently holding. The bit resets when the requested Run mode
output value is within 0.1% of full-scale of the current echo value.
ChxRampAlarm
(2)
Chx.DeviceStatus.RampAlarm
2 This bit is set when the output channel’s requested rate of change would exceed the configured
maximum ramp rate requested parameter. It remains set until the output reaches its target value and
ramping stops. If the bit is latched, it remains set until it is unlatched.
ChxLLimitAlarm
Chx.DeviceStatus.LLimitAlarm 1 This bit is set when the requested output value is beneath the configured low limit value. It remains set
until the requested output is above the low limit. If the bit is latched, it remains set until it is unlatched.
ChxHLimitAlarm
Chx.DeviceStatus.HLimitAlarm 0 This bit is set when the requested output value is above the configured high limit value. It remains set
until the requested output is below the high limit. If the bit is latched, it remains set until it is unlatched.
(1) Bit 6 is not used.
(2) This bit does not set additional bits at any higher level.