Slc Ladder Example - Station 2 Parameter Protocol - Allen-Bradley PowerFlex 20-COMM-P FRN 1 Series User Manual

SLC Ladder Example - Station 2 Parameter Protocol

Figure 6.6 Example SLC Ladder Logic - Station 2 Parameter Protocol
This section of the routine is only needed if the application needs to perform Parameter Protocol Reads or Writes to Station 2.
On power-up, initialize the Parameter Protocol routine.
First Pass
S:1
0015
15
This circuit utilizes the Parameter Protocol. A REQUEST to Station 2 is processed only one at a time, and after each
RESPONSE from Station 2 a zero must be sent and received to 'handshake' before the next REQUEST/RESPONSE transaction
can take place. For example:
Send a parameter read request --> Receive a parameter read response --> Send a "0" --> Receive a "0" --> [Transaction complete]
If the RESPONSE PCA Word 1 (N10:24) is "0", then a REQUEST can be initiated.
Elsewhere in the user program these words must be loaded with message data prior to initiating the REQUEST:
N7:30 = RC = the operation to be performed ("1"=Read, "2" = 16-bit Write, "3" = 32-bit Write)
N7:31 = PNU = the parameter number to read or write
N7:32 = Subindex = the DPI port # ("0"= Host or PowerFlex drive, "5" = 20-COMM-P, etc.)
N7:33 = PVA #1 = the parameter value (high word) - only used when writing parameters
N7:34 = PVA #2 = the parameter value (low word) - only used when writing parameters
The four Parameter Protocol Words set up in the scanner are used to perform the Parameter Protocol:
N20:24 = contains RC (the operation to be performed) and PNU (the parameter number to read or write) combined
N20:25 = Subindex (the DPI port #)
N20:26 = PVA #1 (the parameter value (high word))
N20:27 = PVA #2 (the parameter value (low word))
B3:19/0 is turned ON elsewhere in the program after the REQUEST message (N7:30-34) is loaded. This causes one Parameter
Protocol read or write to occur and B3:19/0 is turned OFF when the transaction is complete.
Station 2
Par Prot Station 2
Messaging RESPONSE
Request PCA Word
B3:19
0016
0
Using Explicit Messaging (Parameter Protocol)
EQU EQU
Equal
Source A N10:24
0<
Source B 0
0<
Station 2
Par Prot
Messaging
Request
B3:19
U
0
Station 2
PCA Word
MOV MOV
Move
Source N7:31
9<
Dest N20:24
0<
PCA Word
RC
RC bit 0 bit 0
N7:30 N20:24
L
0 12
PCA Word
RC
RC bit 1 bit 2
N7:30 N20:24
L
1 13
IND Word
(Subindex)
COP COP
Copy File
Source #N7:32
Dest #N20:25
Length 3
6-13