VIPA CP 240 RS232, Manual

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Chapter 6 CP 240 - M-Bus Manual VIPA System 200V
6-12 HB97E - CP - Rev. 11/30
The following examples show how a telegram is build-up from predefined
data and how the received telegram is stored in the data block.
Assignment via DB Telegram via M-Bus
BBh Baud rate 10h Start
7Bh C field
→
7Bh C field: REQ_UD2
FEh A field FEh A field: PtP Broadcast
79h Check sum of C and A field
16h Stop
ANZ for handling block FC0: 3
Please take care to prefix one byte to every M-Bus telegram that specifies
the baud rate to use.
Telegram via M-Bus storage in DB:
68h 68h Start 00h Response
00h L field
→
08h C field: RSP_UD
03 L field 02h A field: address 02h
68h 68h Start 72h CI field: response variable length
08h C field: RSP_UD 01h
02h A field: address 02h 02h Data field
72h CI field: resp. variable 03h
01h
02h Data field
03h
75h Check sum of
C,A,CI, data
16h Stop
ANZ for handling block FC1: 4
At error-free reception, Byte 0 of the receive-DB contains the value 00h. A
value <> 00h indicates an error.
Here the bits have the following allocation:
Bit 0: set if no answer was received
Bit 1: set in the case of short-circuit at the bus
Bit 2... 7: reserved
Examples
Send data
Baud rate
Receive data
Response byte