Lenze EPM-T1 Series - Page 235

Transmitting parameter data
Reading a parameter (example)
9
Network via CANopen
9.4
9.4.3
L
9.4−5
EDSPM−TXXX−9.0−11/2009
9.4.3 Reading a parameter (example)
An I/O system IP20 has the node address 2. For the first module (4×analog output)
the function of the A.0 output is to be read.
Formula Information
Identifier = Basic identifier + node address
= 1536 + 2 =1538 = 602
h
· Basic identifier for parameter channel 1 (output) = 1536
· Node address of the I/O system IP20 = 2
Instruction
code:
= 40
h
· Command Read Request" (request for reading a
parameter of the I/O system IP20)
Index = I3001
h
· Index first analog module
Subindex = 1 · Subindex = 1 (function for output A.0 among others)
Data 1
Data 2
Data 3
Data 4
Data 1 ... 4
= 00
h
= 00
h
= 00
h
= 00
h
= 00 00 00 00
h
· Read request only
11 bits 8 bytes of user data
Identifier
Instruction
code:
Index
Subindex Data 1 Data 2 Data 3 Data 4
LOW byte HIGH byte
602
h
40
h
01
h
30
h
1 00
h
00
h
00
h
00
h
L
0
1
L
Read Request
Read Response
Identifier = 1538
Identifier = 1410
epm−t119
Fig. 9.4−2 Reading a parameter
Formula Information
Identifier = Basic identifier + node address
= 1408 + 2
= 1410
· Basic identifier for parameter channel 1 (input) = 1408
· Node address of the I/O system IP20 = 2
Instruction
code:
= 43
h
· Command Read Response" (response to the read
request with the current value)
Index = Index of the read request
Subindex = Subindex of the read request
Data 1
Data 2
Data 3
Data 4
Data 1 ... 4
= 00
h
= 00
h
= 05
h
= 3B
h
= 00 00 05 3B
h
· Assumption: Analog output A.0 outputs a voltage signal
0 ... +10 V at a 12 bit resolution.
11 bits 8 bytes of user data
Identifier
Instruction
code:
Index
Subindex Data 1 Data 2 Data 3 Data 4
LOW byte HIGH byte
1410 43
h
01
h
30
h
0 00
h
00
h
05
h
3B
h
(LSB) (MSB)
Task
Telegram to the I/O system IP20
Telegram from the I/O system
IP20 (value of the requested
parameter):