Publication 1769-UM002B-EN-P - July 2005
3-18 Module Data, Status, and Channel Configuration for the Input Modules
1769-IF8 Input Data File
The input data table lets you access analog input module read data for use in
the control program, via word and bit access. The data table structure is shown
in the table below. For each input module, slot x, words 0-7 in the input data
file contain the analog values of the inputs.
1769-IF8 Input Data Values
Words 0 through 7 contain the converted analog input data from the field
device. The most significant bit (MSB) is the sign bit, which is in two’s
complement format. (Nu indicates not used with the bit set to 0.)
General Status Bits (S0 through S7)
Word 9, bits 0 through 7 contain the general operational status bits for input
channels 0 through 7. If set (1), these bits indicate an error associated with that
channel. The over- and under-range bits and the high- and low-alarm bits for
channels 0 through 7 are logically ORed to the appropriate general status bit.
Low Alarm Flag Bits (L0 through L7)
Word 10, bits 3, 7, 11, and 15 and Word 11, bits 3, 7, 11, 15 contain the low
alarm flag bits for input channels 0 through 7. If set (1), these bits indicate the
input signal is outside the user-defined range. The module continues to
convert analog data to minimum full-range values. The bit is automatically
reset (0) when the low alarm condition clears, unless the channel’s alarm bits
are latched. If the channel’s alarm bits are latched, a set (1) low alarm flag bit
clears via the corresponding Clear Alarm Latch bit in your output data file.
Table 3.11 1769-IF8 Input Data Table
Word
Bit Position
1514131211109876543210
0 SGN Analog Input Data Channel 0
1 SGN Analog Input Data Channel 1
2 SGN Analog Input Data Channel 2
3 SGN Analog Input Data Channel 3
4 SGN Analog Input Data Channel 4
5 SGN Analog Input Data Channel 5
6 SGN Analog Input Data Channel 6
7 SGN Analog Input Data Channel 7
8 Nu Time Stamp Value
9 Nu NuNuNuNuNuNuNuS7S6S5S4S3S2S1S0
10 L3 H3 U3 O3 L2 H2 U2 O2 L1 H1 U1 O1 L0 H0 U0 O0
11 L7 H7 U7 O7 L6 H6 U6 O6 L5 H5 U5 O5 L4 H4 U4 O4
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