Rockwell-automation 20-COMM-I Interbus Adapter Bedienungsanleitung PDF herunterladen (Seite 68)

6-6 Using Explicit Messaging (PCP Communications)

The example ladder logic program simplifies addressing the various PCP

indexes. Before calling the PCP Read Subroutine (Figure 6.3), three

registers are loaded to identify the variable to be read:

Table 6.2 PCP Read Main Program Data

The PCP Read Subroutine uses the data in Table 6.2 to create the

following Command Message:

Table 6.3 PCP Read Subroutine Command Message

Table 6.4 PCP Read Subroutine Reply Message

N22:0

The Communication Reference (CR) to read from:

Set to “2” to access Station 1.0 (CR=2)

Set to “3” to access Station 2.0 (CR=3)

N22:1

The desired Parameter / Event / Fault area to be accessed:

Set to “0” to read PowerFlex 70 parameters

Set to “1” to read 20-COMM-I parameters

Set to “2” to read PowerFlex 70 Fault Queue

Set to “3” to read 20-COMM-I Event Queue

N22:2

The actual Parameter number or Event / Fault Queue item

number to read. Set to “1” to read Parameter number 1 or Fault / Event

Queue item number 1....etc....

N22:10 The PCP Command word (set to “4” for PCP Read).

N22:11 The Communication Reference (CR) to read from.

N22:12 The PCP Index of the variable to read (“3001h”= Host parameter 1, etc.).

N22:13 Sub Index not used (set to “0”).

N22:20 = PCP Status Word.

N22:21 = Echo of the Command word (0004h).

N22:22 = Number of words following.

N22:23 = CR.

N22:24 = Result (“0”=good).

N22:25 = Number of bytes read (1-byte for 8-bit Parameters,

2-bytes for 16-bit Parameters, 4-bytes for 32-bit Parameters).

N22:26 = Data Word #1 (1-byte & 2-byte reads, MSW of 4-byte

read).

N22:27 = Data Word #2 (LSW of 4-byte read).

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Rockwell-automation 20-COMM-I Interbus Adapter Bedienungsanleitung Seite 68