Networking via system bus (can), Transmitting parameter data telegram structure – Lenze EPM−T9XX Modular system User Manual
Page 188

Transmitting parameter data
Telegram structure
Networking via system bus (CAN)
8.4
8.4.1
L
8.4−2
EDSPM−TXXX−9.0−11/2009
Identifier
Instruction
code
Index
Subindex
Data 1
Data 2
Data 3
Data 4
LOW byte HIGH byte
The instruction code contains the command to be executed and information about
the parameter data length. It is structured as follows:
bits 7
(MSB)
bits 6
bits 5
bits 4
bits 3
bits 2
bit 1
bit 0
Command
Command Specifier (cs)
Length
E
s
Write Request
0
0
1
0
00 = 4 bytes
01 = 3 bytes
10 = 2 bytes
11 = 1 byte
1
1
Write Response
0
1
1
0
0
0
Read Request
0
1
0
0
0
0
Read Response
0
1
0
0
1
1
Error Response
1
0
0
0
0
0
0
0
Instruction code for parameters with 4 bytes of data length:
4 bytes of data
(32 bits)
Command
hex
dec
Information
Write Request
23
35
Transmitting parameters to a node
Write Response
60
96
Node response to the Write Request (acknowledgement)
Read Request
40
64
Request to read a parameter from a node
Read Response
43
67
Response to the read request with the actual value
Error Response
80
128
Node reports a communication error
If an error occurs, the addressed node generates an Error Response".
In Data 4, this telegram always contains the value 6", in Data 3 it contains an error
code:
Command code Error Response
Data 3
Data 4
Error message
80
h
3
6
Access denied
5
Wrong subindex
6
Wrong index
Instruction code
Instruction Error Response"