Allen-Bradley MicroLogix 1200 Reference Manual page 27

Analog I/O Configuration
1769-IF4 Input Data File
For each input module, words 0 through 3 contain the analog values of
the inputs.
Bit Position
15 14 13 12
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 not used
5 U0 O0 U1 O1 U2 O2 U3 O3 Set to 0
The bits are defined as follows:
• SGN = Sign bit in two's complement format.
• Sx = General status bits for channels 0 through 3. This bit is set (1)
when an error (over- or under-range) exists for that channel.
• Ux = Under-range flag bits for channels 0 through 3. These bits can be
used in the control program for error detection.
• Ox = Over-range flag bits for channels 0 through 3. These bits can be
used in the control program for error detection.
1769-OF2 Output Data File
For each module, words 0 and 1 in the output data file contain the
channel 0 and channel 1 output data.
Bit Position
15 14 13 12
0 SGN Channel 0 Data 0 to 32,768
1 SGN Channel 1 Data 0 to 32,768
SGN = Sign bit in two's complement format.
11 10 9 8 7 6
11 10 9 8 7 6
I/O Configuration 1-11
5 4 3 2 1 0
S3 S2 S1 S0
5 4 3 2 1 0
Publication 1762-RM001C-EN-P