Rockwell Automation 1771-IE,D17716.5.7 ANAL.INPUT MOD. - Manual (Page 43)

Single Channel Transfer for PLC Processor
Appendix B
BĆ6
In single channel transfer, the processor transfers data one byte at a time.
Your program must reconstruct the data into 16-bit words in the correct
sequence. We developed a flow chart (Figure B.2) that describes single
transfer programming to help you understand the logic.
Figure B.2
Flow Chart for PLC Example Program
Start
Increment I/O
Is Yes Set Update
No
Is Yes
Reset Update
No
Is No
Yes
Store input word
Set Byte SELECT
Rung
1-3
29 30
4
5
Is
No
Yes
1. Store input word (110) containing
6
7
8-15
16
17-24
26
27
28
Set Channel
29-35
Have
Yes
Reset both scan
36, 37
No
To balance of program
14161
scan counter
(200)
No.
Scan count
<3?
SELECT bits
Scan count
= 3?
Channel No. 1
SELECT
command.
(Bits 0-6 of output
byte OFF.)
SELECT bits. Set
Scan count
= 5?
Scan count
= 7?
(110) containing
low byte
bit to 1. (Selects
High Byte.)
Rung
No.
high byte.
2. Reconstruct channel word.
3. Check Module fault diagnostics.
4. Store channel word.
5. Reset Byte SELECT bit.
6. Increment Reference Counter (203).
7. Load Scan Counter (200) with 002.
SELECT bits
all Module
Channels been
Read?
(Does CTU 203
= 8?)
and reference
counters (200
and 203)
Program Logic