Rockwell Automation 1771-N SERIES High Resolution Analog Module User Manual - Manual (Page 61)

Chapter
5
Publication 1771ĆUM127B-EN-P - December 2002
Module Status and Input Data
In this chapter you will read about:
• reading data from your module
• block transfer read data format
Block transfer read (BTR) programming moves status and data from
the module to the processor’s data table in one I/O scan. The
processor user program initiates the request to transfer data from the
module to the processor.
The transferred words contain module status, channel status and
input data from the module. The maximum BTR data file length
required is 28 words.
Block transfer reads are defined for each type of module platform,
rather than type of outputs/inputs. The types of modules are:
Possible Combinations Appendix
8 out/0 in C
7 out/1 in K
6 out/ 2 in I
5 out/ 3 in J
4 out/4 in H
3 out/5 in G
2 out/6 in E
1 out/ 7 in F
0 out/8 in B
2 out/2 in D
For example, the BTR from the 1771-NB4T (two 0-25mA out/two
thermocouple in) is identical to the BTR for the 1771-NB4S (two
0-25mA out/two 4-20mA in), since both are 2 input/2 output
modules.
When you perform a BTR for a specific module, the bits for fields
that do not pertain to your specific module are set to zero.
Complete block transfer read data formats and bit/word descriptions
for your particular module are shown in the Appendices.
Chapter Objectives
Reading Data from the
Module