Manual

86 Publication 1756-UM0009C-EN-P - December 2010
Chapter 4 Non-isolated Analog Voltage/Current Input Modules (1756-IF16, 1756-IF8)
1756-IF8 Fault Reporting in
Floating Point Mode
The illustration describes the fault reporting process for the 1756-IF8 module
in floating point mode.
15 14 13 12 11
543210
54321076
15 = AnalogGroupFault
10 = Calibrating
9 = Cal Fault
14, 13, 12, and 11 are
not used
7 = Ch7Fault
6 = Ch6Fault
5 = Ch5Fault
4 = Ch4Fault
3 = Ch3Fault
2 = Ch2Fault
1 = Ch1Fault
0 = Ch0Fault
7 = ChxCalFault
6 = ChxUnderrange
5 = ChxOverrange
4 = ChxRateAlarm
41514
If set, any bit in the Channel Fault word, also sets the
Analog Group Fault in the Module Fault word
A channel calibration fault
sets the calibration fault in
the Module Fault word
3 = ChxLAlarm
2 = ChxHAlarm
1 = ChxLLAlarm
0 = ChxHHAlarm
An underrange, overrange condition
sets appropriate Channel Fault bits
When the module is calibrating, all
bits in the Channel Fault word are set
10 9
76
Eight channels used in S.E. wiring
Four channels used in Diff. wiring
Two channels used in H.S. Diff. wiring
All start at bit 0
Alarm bits 0…4 in the Channel Status word
do not set additional bits at any higher level.
You must monitor these conditions here.
The number of channel status words is
dependent on the communication
method used
Module Fault Word
(described on
page 87 )
Channel Fault Word
(described on page 87 )
Channel Status Words
(One for each channel–described
on
page 88 )