Binary Record - Parker Compax3 Series Operating Instructions Manual

Parker EME
5.2

Binary record

Basic structure:
Start code Address
SZ O
The start code defines the frame type and is composed as follows:
Bit
Frame type
RdObj Read object
WrObj Write object
Rsp Answer
Ack Positive command acknowledgement
Nak Negative command acknowledgement
Request telegrams
Response telegram
The binary record with block securing is based on 5 different telegrams:
2 request telegrams which the control sends to Compax3 and
!
3 response telegrams which Compax3 returns to the control.
!
Telegram layout
Number of data bytes - 1
L
Bits 7, 6, 5 and 4 of the start code form the telegram identification; Bit 2 is always
"1".
Bits 3, 1 and 0 have different meanings for the request and response telegrams.
The address is only necessary for RS484.
-> Compax3
the address bit (Bit 0 = 1 ) shows if the start code is followed by an address (only
!
for RS485; for RS232 Bit 0 = 0)
the gateway bit (Bit 1 = 1) shows if the message is to be passed on.
!
(Please set Bit 1 = 0, as this function is not yet available)
the PLC bit (Bit 3 = 0 ) allows access to objects in the PLC format (U16, U32,
!
IEEE Floating Point). For information into which PLC format the objects are
converted, please refer to the object description.
Compax3 ->
Bits 0 and 1 are used to identify the response
!
Bit 3 is always 0
!
The maximum number of data bytes in the request telegram is 256, in the response
telegram 253.
The block securing (CRC16) is made via the CCITT table algorith for all characters.
After receiving the start code, the timeout monitoring is activated in order to avoid
that Compax3 waits in vain for further codes (e.g. connection interrupted) The
timeout period between 2 codes received is fixed to 5ms (5 times the code time at
9600Baud)
I11 T11 192-120101 N6 - March 2004
Data
D0 D1
7 6 5 4
Frame identification
1 0 1 0
1 1 0 0
0 0 0 0
0 0 0 0
0 0 0 0
RS232 & RS485 – interface record
block securing
... Dn Crc(Hi)
3 2 1
PLC Gateway
x 1 x
x 1 x
0 1 0
0 1 1
0 1 1
Crc(Lo)
0
Address
x
x
1
0
1
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