Rockwell Automation 1771-IE,D17716.5.7 ANAL.INPUT MOD. - Manual (Page 7)

Overview of the Analog Input Module
Chapter 2
2Ć3
Figure 2.2
Communication Between Input Module and Processor
8- BIT Input Module
(cat. no. 1771-IE)
Input
Device
1
2
3
4 5
14164
PC Processor
(PLCĆ2/30 Processor
Shown)
BTR
1. Input devices generate analog signals which are transmitted to the
input module.
2. The input module converts analog signals into BCD values and
stores them until the processor requests a transfer of data.
3. When instructed by your ladder diagram program, the processor
performs a read block transfer of the values and stores them in its
data table.
4. Your program can determine that the transfer was made without
error, and that the values are within a specified range.
5. Your program can use and/or move the data before it is written over
by the transfer of new data in a subsequent block transfer.
The input module converts analog signals to digital values readable by
your processor (Figure 2.3).
The input module scans its inputs every 2.5ms and converts analog data to
a digital format. It stores this data momentarily until transferred to the
processor’s data table. The module reserves the last 200 microseconds of
How the Input Module Converts
Analog Signals