![Parker Compax3 C3I20T11 Operating Instructions Manual Download Page 298](http://html1.mh-extra.com/html/parker/compax3-c3i20t11/compax3-c3i20t11_operating-instructions-manual_3811584298.webp)
Communication
C3I20T11 / C3I32T11
298
192-120103 N13 C3I20T11 / C3I32T11 December 2010
Write object - WrObj telegram
SZ
Adr
L
D0
D1
D2
D3 ... Dn
Crc(Hi)
Crc(Lo)
0xCX
n
Index(Hi)
Index(Lo)
Subindex
Value
0x..
0x..
Describing an object by a value.
Positive acknowledgement - Ack-telegram
SZ
L
D0
D1
Crc(Hi)
Crc(Lo)
0x06
1
0
0
0x..
0x..
Answer from Compax3 if a writing process was successful, i.e. the function could
be executed and is completed in itself.
Negative acknowledgement - Nak - telegram
SZ
L
D0
D1
Crc(Hi)
Crc(Lo)
0x07
1
F-No.(Hi)
F-No.(Lo)
0x..
0x..
Answer from Compax3 if access to the object was denied (e.g. function cannot be
executed at that point in time or object has no reading access). The error no. is
coded according to the DriveCom profile resp. the CiA Device Profile DSP 402.
Read object - RdObj - telegram
SZ
Adr
L
D0
D1
D2
D3
D4
D5
...
Dn
Crc(Hi)
Crc(Lo)
0xAX
n
Index1(Hi) Index1(Lo) Subindex1 Index2(Hi)
Index2(L
o)
Subindex2 ...
...
0x..
0x..
Reading one or several objects
Answer - Rsp - telegram
SZ
L
D0 ... Dx-1
Dx ... Dy-1
Dy-D..
D ... D..
D ... Dn
Crc(Hi)
Crc(Lo)
0x05
n
Value1
Value 2
Value 3
Value ..
Value n
0x..
0x..
Answer from Compax3 if the object can be read.
If the object has no reading access, Compax3 answers with the Nak - telegram.
Reading object "StatusPositionActual" (o680.5):
Request: A5 03 02 02 A8 05 E1 46
Response: 05 05 FF FF FF FF FE 2D 07 B4
Writing into an Array (o1901.1 = 2350)
Request: C5 02 08 07 6D 01 00 09 2E 00 00 00 95 D5
Response: 06 01 00 00 BA 87
Checksum calculation for the CCITT table algorithm
The block securing for all codes is performed via the following function and the
corresponding table:
The “CRC16” variable is set to “0” before sending a telegram.
CRC16 = UpdateCRC16(CRC16, Character);
This function is called up for each Byte (Character) of the telegram.
The result forms the last two bytes of the telegram
Compax3 checks the CRC value on receipt and reports CRC error in the case of a
deviation.
Example:
Block securing:
Function call: