Rockwell Automation 1769-OF4VI Compact I/O Isolated Analog Modules - Manual (Page 42)

Publication 1769-UM014B-EN-P - May 2010
3-4 Module Data, Status, and Channel Configuration for the Input Module
High Alarm Flag Bits (H0 to H3)
Word 6, bits 2, 6, 10, 14 contain the high alarm flag bits for input channels 0 to
3 and applies to all input types. If set (1), the input signal is outside 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 to O3)
Over-range bits for channels 0 to 3 are contained in Word 6, 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 to U3)
Under-range bits for channels 0 to 3 are contained in Word 6, 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 any voltage range or 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 4)
The 1769-IF4I supports a 15-bit rolling timestamp that is updated during each
new update of the analog input values. The timestamp has a 1 ms resolution.
The timestamp value is placed in the Input Data file, word 4, for each module
input data update (if the timestamp function is enabled). Enable and/or
disable this timestamp in word 1, bit 15 of the Configuration Data file.