Communication protocols
PROGRAMMING MANUAL 237
Revision 1.0
4.6.3 Communication operation
When the communication is in progress, specific data can be exchanged
with the CAN_CORT command.
1. To set the CANopen network state to pre-operational or operational,
execute the command CAN_CORT(unit,11,mode).
2. To read the value of an object of a CANopen node with an SDO (Service
Data Object) command, execute the command
CAN_CORT(unit,12,node_ID,index,subindex,VR_address).
Each byte of the return value occupies one VR address. The first
address (VR_address) contains the SDO response byte. The data read
starts at VR_address + 1.
When the SDO response is not 0, the error information from the node
unit starts at VR_address + 1.
3. To write a value to an object of a CANopen node with an SDO command,
execute the command
CAN_CORT(unit,13,node_ID,index,subindex,VR_address,data_len).
Each VR address is interpreted as one byte of the value that is written.
4. To read the EMCY (emergency message from a node, execute the
command CAN_CORT(unit,14,node_ID,VR_address).
Each byte of the 8 bytes occupies 1 VR address.
4.7 MECHATROLINK-II
The MECHATROLINK-II protocol is a serial bus that is made to control
motion in a deterministic way.
The number of MECHATROLINK-II devices determines the data exchange
cycle time:
• For 1 to 4 devices the cycle time can be 0.5 ms, 1 ms or 2 ms.
• For 5 to 8 devices the cycle time can be 1 ms or 2 ms.
• For 9 to 16 devices the cycle time is 2 ms.
The cyclic transmission has two stages:
• The TJ1-ML__ sends the reference command to the MECHATROLINK-II
slaves.
• The slaves send feedback and status information to the TJ1-ML__.
The MECHATROLINK-II uses a synchronization clock and broadcast
messaging to make sure that all the slaves execute the commands at the
same time.
In addition, other information is transferred at a lower rate, for example the
reading and writing of parameters.
There are specific BASIC commands to address MECHATROLINK-II slave
units directly.
• DRIVE_CLEAR: This command resets one alarm in a
MECHATROLINK-II Servo Driver via a MECHATROLINK-II message.
• OP(45,ON): This command sets to on one output in a remote
MECHATROLINK-II I/O module.
4.8 GRT1-ML2 I/O mapping
The GRT1-ML2 SmartSlice I/O Unit is an interface for data exchange
between a TJ1-ML__ MECHATROLINK-II Master Unit and SmartSlice I/O
Units.
If you plan data exchange that requires strict control of the I/O timing, refer
to appendix A. This appendix also contains some useful examples.
4.8.1 Unit numbers
The GRT1-ML2 must have a MECHATROLINK-II address to be identified on
the MECHATROLINK-II network. With this address, the TJ2-MC64
connected to the TJ1-ML__ can exchange I/O data with the GRT1-ML2.
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