Spectrum Controls 1771sc-IFE32 - Manual (Page 13)

Chapter 1: Overview of the Analog Input Module 3
3. The module converts analog signals into binary or BCD format, and stores these
values until the processor requests their transfer.
4. When instructed by your ladder program, the processor performs a read block
transfer of the values and stores them in a data table.
5. The processor and module determine that the transfer was made without error, and
that input values are within specified range.
6. Your ladder program can use and/or move the data (if valid) before it is written over
by the transfer of new data in a subsequent transfer.
7. Your ladder program should allow write block transfers to the module only when
enabled by operator intervention or at power-up.
Accuracy
The accuracy of your input module is described in Appendix A.
Chapter Summary
In this chapter you read about the functional aspects of the input module and how
the module communicates with the programmable controller.