Omron C200HW-CORT21-V1, Operation Manual

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Message communication
Section 5-1
70
5-1 Message communication
Functions
The message communication is used for the following functions:
1. Reading the error log
2. Writing to the local CANopen object dictionary
3. Reading from the local CANopen object dictionary
4. Transmitting a user-defined CAN message
5. Receiving a user-defined CAN message
The error log stores the 25 most recent errors that have occurred due to
message communication. These errors can be read with the IORD
instruction.
Functions 2 and 3 can be used to read and modify the object dictionary of the
Unit.
In order to provide additional flexibility for advanced users, the Unit can be
used to transmit and receive user-defined CAN messages. This allows
interfacing the C200HW-CORT21-V1 with devices that operate according to
vendor- or application-specific CAN-based protocols, different from
CANopen. This functionality can be used simultaneously with the CANopen
communication.
The next sections will first describe the general use of the IOWR / IORD
instructions and the error log. After that, the five message communication
functions of the C200HW-CORT21-V1 are explained in detail.
5-2 IOWR / IORD
The ladder symbols for IOWR and IORD are shown below.
IOWR (-) @IOWR (-)
C C
S S
D D
C
Control code
value: Specifies the function to execute (see below)
S
First source word
value: The start address of the PLC data area that contains the
message to be transferred to the Unit.
D Destination information
On C200H Alpha PLCs:
value: Combination of the Machine number of the target Unit and
the message length (number of words in BCD).
Message length (001 ~ 128)
Machine number (0 ~ F)
On CS1 PLCs:
The Machine Number and message length occupy 2 words:
D: Machine number of the Unit
D+1: Message length (number of words in BCD)