System bus (CAN) with Servo PLC & Drive PLC
System blocks
6.3
CAN2_IO
6-13
L
PLC-Systembus EN 1.1
Process data telegram
The process data telegram consists of an
identifier
and 8 bytes of user data.
11-bit
8-byte user data
Identifier
Byte 1
Byte 2
Byte 3
Byte 4
Byte 5
Byte 6
Byte 7
Byte 8
Identifier
Information about the identifier can be found in chapter 2.3.1.
User data
The first 4 of the 8 bytes of user data to be sent can be written by several variables of a different data
type at the same time and can therefore - as required - be transmitted as
•
binary information (1-bit)
•
quasi-analog value (16-bit)
•
phase-angle information (32-bit)
from the PLC program:
Byte
Variable (1-bit)
Variable (16-bit)
Variable (32-bit)
1, 2
CAN2_bFDO
0
_b
...
CAN2_bFDO
15
_b
CAN2_nOutW1_a
CAN2 dnOutD1 p
3, 4
CAN2_bFDO
16
_b
...
CAN2_bFDO
31
_b
CAN2_nOutW2_a
CAN2_dnOutD1_p
5, 6
CAN2_nOutW3_a
7, 8
CAN2_nOutW4_a
Tip!
Make sure that a byte to be transmitted is not at the same time written by different variable types to
ensure data consistency.
•
For writing bytes 1 and 2, either use only the variable
CAN2_dnOutD1_p
, only the variable
CAN2_nOutW1_a
or only the variables
CAN2_bFDO0_b
...
CAN2_bFDO15_b
.
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