3 parameter protocol examples – Rockwell Automation RECOMM-PBUS PROFIBUS Communications Module User Manual
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7-6
PROFIBUS Communications Module
7.3.3 Parameter Protocol Examples
Read Examples
Request
Response
RC
Set to “1” (‘0001’) binary to read
RC
“1” (‘0001’) Transferring 8-bit or 16-bit parameter
value
“2” (‘0010’) Transferring a 32-bit parameter value
“7” (‘0111’) Request rejected (including fault code)
SPM
Not used
SPM
Not used
PNU
Parameter number to read
PNU
Confirms the Parameter number (if successful,
equals the PNU from the request)
Subindex
Selects which DPI port to talk to (“0” =
DPI Host, “5” = RECOMM-PBUS on
SP600 drives).
Subindex
Confirms the DPI port (if successful, equals the
Subindex from the request)
Not Used
Parameter value high word
Contains a “0” if returning a value from a 16-bit
parameter and the high word from a 32-bit
parameter
Not Used
Parameter value low word
Contains the value from a 8-bit or 16-bit parameter,
the low word if reading from a 32-bit parameter, or
the fault code (if RC = “7”)
Bit 15-12
11
10-0
15-12
11
10-0
Parameter Access
Word 1 (PCA)
RC
SPM
PNU
RC
SPM
PNU
Parameter Access
Word 2 (IND)
Subindex
Subindex
Parameter Access
Word 3 (PVA)
Not Used
Parameter value high
(32-bit high word)
Parameter Access
Word 4 (PVA)
Not Used
Parameter value low
(32-bit low word/ or
8-bit/16-bit value)
Request
Response