Precautions For Dedicated Instructions - Mitsubishi Electric MELSEC iQ-R Series User Manual

3.2

Precautions for Dedicated Instructions

Before executing the dedicated instruction
Always check the following points before executing the data consistency dedicated instruction.
■Enabling the dedicated instructions
Set the data consistency setting according to the setting of the mode switch as follows. ( Page 40 Master/Slave Function
Common Parameters)
Mode switch setting
0 to 2
3 to 5
6 to 8
When the data consistency setting does not match the mode switch setting, an error occurs, and either of 'Master function
error set signal' (X03) or 'Slave function error set signal' (X08) turns on, or both of them turn on.
In this case, the data consistency function is disabled. Set the parameters correctly.
When the data consistency settings which are different from the settings above are set, the data consistency
dedicated instruction is not executed. In addition, an error does not occur.
■Access to the transmit/receive data areas of the buffer memory without using the dedicated
instruction
When using the data consistency dedicated instruction, do not access the transmit/receive data areas of the buffer memory
with the following methods. Otherwise, data inconsistency may occur.
• Refresh
• MOV instruction
• FROM/TO instruction
The target transmit/receive data areas of the buffer memory are as follows.
• 'Master function receive data' (Un\G1792 to Un\G2047)
• 'Master function transmit data' (Un\G2304 to Un\G2559)
• 'Slave function receive data' (Un\G2816 to Un\G2879)
• 'Slave function transmit data' (Un\G3072 to Un\G3135)
Transmission delay time when the dedicated instruction is used
When the data consistency dedicated instruction is used, the transmission delay time will become longer. ( Page 96
Transmission delay time)
Execution timing of the dedicated instruction
After enabling the data consistency setting, execute the data consistency dedicated instruction once in one sequence scan.
3 DEDICATED INSTRUCTION
46
3.2 Precautions for Dedicated Instructions
Master function
Slave function
Master function + slave function
Data consistency setting
Only master function instruction is enabled
Only slave function instruction is enabled
Select one of the following settings.
• Only master function instruction is enabled
• Only slave function instruction is enabled
• Master function and Slave function instruction are enabled