Rockwell Automation 1769-OF2 Compact I/O Analog Modules - Manual (Page 69)

Publication 1769-UM002B-EN-P - July 2005
Module Data, Status, and Channel Configuration for the Input Modules 3-19
High Alarm Flag Bits (H0 through H7)
Word 10, bits 2, 6, 10, 14 and Word 11, bits 2, 6, 10, 14 contain the high alarm
flag bits for input channels 0 through 7 and applies to all input types. If set (1),
the input signal is output the user-defined range. The module continues to
convert analog data to maximum full-range values. The bit is automatically
reset (0) when the high alarm condition clears, unless the channel’s alarm bits
are latched. If the channel’s alarm bits are latched, a set (1) high alarm flag bit
clears via the corresponding Clear Alarm Latch bit in your output data file.
Over-Range Flag Bits (O0 through O7)
Over-range bits for channels 0 through 7 are contained in Word 10, bits 0, 4, 8,
12 and Word 11, bits 0, 4, 8, 12. They apply to all input types. When set (1),
this bit indicates input signals beyond the normal operating range. 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 through U7)
Under-range bits for channels 0 through 7 are contained in Word 10, bits 1, 5,
9, 13 and Word 11, bits 1, 5, 9, 13. They apply to all input types. When set (1),
this bit indicates input signals below the normal operating range. It may also
indicate an open circuit condition, when the module is configured for the 4 to
20 mA range. 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.
Time Stamp Value (Word 8)
The 1769-IF8 supports a 15-bit rolling timestamp that is updated during each
new sampling period of the analog inputs. The timestamp has a 1 ms
resolution. The timestamp value is placed in the input image file, word 8, for
each module input data update (if the timestamp function is enabled). Enable
and/or disable this timestamp in the configuration file.