Parker EME
Communication
192-120103 N13 C3I20T11 / C3I32T11 December 2010
329
5.4.4.
Acyclic parameter channel
In this chapter you can read about:
Parameter access with DPV0: Required data channel ...................................................329
Compax3 - objects for the parameter channel ................................................................335
Compax3 supports parameter access with DPV1.
5.4.4.1
Parameter access with DPV0: Required data channel
You can use the PKW mechanism for acyclic access to parameters in cyclic data
exchange as well. This is made available to make it possible for the
master/controller to have access to the important device parameters without DPV1
functionality.
The master/controller formulates an order in the PKW mechanism. Compax3
processes the order and formulates the response.
PKW structure:
Byte 1
Octet 2 Octet 3 Octet 4 Octet 5
Octet 6 Octet 7 Octet 8
PKE
IND
PWE
PKW:
Parameter identification value
PKE:
Parameter identification (1st and 2nd byte) (see below)
IND:
subindex* (3rd byte), 4th byte is reserved
PWE:
Parameter value (5th through 8th byte or 5th through 12th byte with expanded PKW)
PKE structure:
Byte 1
Octet 2
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
AK
SPM PNU
AK:
Order or response identification (value range 0 ... 15)
SPM:
reserved
PNU:
Parameter number
*Reference to the subindex
The information for PNU subindex (parameter number) also applies to PROFIdrive
profile Version 3, i.e., that the subindex is counted starting at 0, while for
PROFIdrive profile Version 2 the subindex is counted starting at 1:
DPV1-
Client (V3)
PKW-
Client (V2)
[1..n]
[0..n-1]
Drive
(V3)
[0..n- 1]
-1
The result of this is as follows:
Profibus master based on PROFIdrive profile Version 3
The subindex of the Profibus No. (PNU) specified in the object list is directly valid.
Example: Example: PNU object forward speed control = 400.1 (as specified).
Profibus master based on PROFIdrive profile Version 2
The subindex of the Profibus No. (PNU) specified in the object list must be
incremented by 1.
Example: PNU object forward speed control = 400.2