Rockwell Automation 20-COMM-I Interbus Adapter - Manual (Page 71)

Using Explicit Messaging (PCP Communications) 6-9
Reading Pr. 21 [PIDD W0 Actual] from a 20-COMM-I
In the example ladder logic program, the user would load these
registers before calling the subroutine to perform the PCP read:
Echo of the Command Word (PCP Read)
Message
Command word = 4 = PCP Read (bit 2 ON) N22:10 Command 4 4
SLC Address Descr
iption
Value (He
x)
N22:22
N22:13
N22:12
N22:11
N22:23
Reply
2
4
-32,764
0
2
4
CR# = 2 (Station 1.0)
Sub Index not used
Number of words following = 4
CR# = 2 (Station 1.0)
2FCA
2
4
2
4
N22:21
0
8004
Value (Dec)
N22:20
Result = 0 (success)
N22:25
N22:26
0
12186
2 Number of bytes read = 2
Data word 2 not used
0
2F9A
2
N22:24
N22:27 0 0
"8000" (bit 15 ON) indicates Reply message present
Status word:
"0004" (bit 2 ON) echo's the command (PCP Read)
2FB6h is the start of the 20-COMM-I parameters (Pr.1)
Index =2FB5h+15h = Parameter 21 [PIDD W0 Actual]
15 hex = 21 dec = Parameter 21 [PIDD W0 Actual]
Data word 1 = 2F9A hex = Logic Status
12234
Message
CR# = 2 (Station 1.0)
N22:0 Request 2 2
SLC Address Desc
ription
Value (He
x)
N22:1 1 1= 20-COMM-I 1
Value (Dec)
N22:3 21 15 Parameter # = 21 [PIDD W0 Actual]
20COMM-UM007A-EN-P.book Page 9 Tuesday, January 22, 2002 10:52 AM