Fieldbus Specific Mailbox Commands
3-7
Set the PDU sizes (SET_PDU_SIZES)
This mailbox sets the sizes of the input and output PDU (Protocol Data Unit), which sets up the trans-
mit and receive buffers used for PCP communication. In case larger objects are to be downloaded by
the SET_PCP_OBJECT mailbox, it might be necessary to increase the PDU-sizes. The buffers should
be at least 6 bytes larger than the payload data of the objects.
Command and response layout:
Parameter
Description
Command initiator
Application
Command Name
SET_PDU_SIZES
Message type
02h
Command number
0005h
Fragmented
No
Extended Header data
-
Command data
PDU lengths (Receive and Transmit is related to the Anybus-S node)
Response data
PDU lengths. If error code Fh is returned please see the Extended word 8 for further infor-
mation.
0001h - PDU length less than 51
0002h - PDU length larger than 246
Command
Expected response
Message ID
(ID)
(ID)
Message information
4002h
0002h
Command
0005h
0005h
Data size
0002h
0002h
Frame count
0001h
0001h
Frame number
0001h
0001h
Offset high
0000h
0000h
Offset low
0000h
0000h
Extended word 1
-
-
Extended word 2
-
-
Extended word 3
-
-
Extended word 4
-
-
Extended word 5
-
-
Extended word 6
-
-
Extended word 7
-
-
Extended word 8
-
Fault information
Message data byte 1
Receive PDU length
Receive PDU length
Message data byte 2
Transmit PDU length
Transmit PDU length
