Rockwell Automation 5370 Color CVIM Communications Manual - Manual (Page 45)

Chapter 4
Using the Remote I/O Link
4–8
A PLC can directly access discrete bit information using a simple ladder
program. For example:
You can use the following rung to examine the data valid bit and energize an
output if the data is valid. Refer to Chapter 3 for a description of the local
I/O. This example assumes that the Color CVIM module is in Rack 02 and
the output device is in Rack 01.
Although the same basic information is provided in Appendix B, Tables 4.A
and 4.B illustrate the word and bit locations of the discrete bits that can be
read or manipulated using simple ladder programs. We have organized the
data so that it is formatted similar to a PLC setup screen. Table 4.A shows
the first part of discrete bits results (Color CVIM module to PLC). Table 4.B
shows the second part. You can tell the difference by examining word 0, bit
5, which has a value of 0 for the first part and 1 for the second part. Table
4.C shows the Color CVIM remote outputs (PLC to Color CVIM module).
Important Note: To read results data, you must set one of the following bits
(assuming Color CVIM module is rack 02):
O:22/00 (Post First Part of Results to Remote I/O)
O:22/01 (Post Second Part of Results to Remote I/O)
Note to PLC–2 Users:
When you use any PLC–2 family processor with the Color CVIM module,
you should understand the operation of the PLC Block Transfer Done bits for
Read and Write instructions. PLC–2 family processors use the input image
table for these bits, all other PLCs can specify integer files for this function.
This means that a PLC–2 user must use proper programming techniques to
avoid confusion between the following bits:
Color CVIM module discrete I/O input word 0, bit 6 (data valid) and bit 7
(not used).
PLC–2 family input image table word 0, bit 6 (BTW done bit) and bit 7
(BTR done bit).
Remember that word 27 is a reserved word in the PLC–2 data table, and
should not be used for any other purpose.
Accessing Discrete
Bit Information