Rockwell Automation 1769-IF16V Compact High Density Analog Input Modules - Manual (Page 33)

Publication 1769-UM018A-EN-P - October 2008 33
Module Data, Status, and Channel Configuration Chapter 3
Over-Range Flag Bits (O0…O15)
Over-range bits for channels 0…15 are contained in Words 18…21,
bits 0, 4, 8, and 12. When set (1), this bit indicates an input signal is
beyond the normal operating range. For the 1769-IF16V module, it
may also indicate an open circuit condition. However, the module
continues to convert analog data to the maximum full range value.
The bit is automatically reset (0) by the module when the over-range
condition is cleared and the data value is within the normal operating
range.
Under-Range Flag Bits (U0…U15)
Under-range bits for channels 0…15 are contained in Words 18…21,
bits 1, 5, 9, and 13. When set (1), this bit indicates an input signal is
below the normal operating range. For the 1769-IF16C module, it may
also indicate an open circuit condition. However, the module
continues to convert analog data to the minimum full range value. The
bit is automatically reset (0) by the module when the under-range
condition is cleared and the data value is within the normal operating
range.
Output Data File The output data table lets you access analog output module write data
for use in the control program, via word and bit access.
These bits are written during run mode to cancel any latched low- and
high-process alarms. The alarm is unlatched when the unlatch bit is
set (1) and the alarm condition no longer exists. If the alarm condition
persists, then the unlatch bit has no effect until the alarm condition no
longer exists. You need to keep the unlatch bit set until verification
from the appropriate input channel status word that the alarm status
bit has cleared (0). Then you need to reset (0) the unlatch bit. The
module will not latch an alarm condition if a transition from ‘no alarm’
to ‘alarm’ occurs while a channel’s cancel latch bit is set.
Word/
Bit 15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00
Word 0 CLL7 CLH7 CLL6 CLH6 CLL5 CLH5 CLL4 CLH4 CLL3 CLH3 CLL2 CLH2 CLL1 CLH1 CLL0 CLH0
Word 1 CLL15 CLH15 CLL14 CLH14 CLL13 CLH13 CLL12 CLH12 CLL11 CLH11 CLL10 CLH10 CLL9 CLH9 CLL8 CLH8