Mitsubishi Electric MELSEC iQ-R Series User Manual page 49

Operation when the dedicated instruction is unexecuted
If the dedicated instruction is not executed in three sequence scans after the data consistency setting is enabled, an error
occurs.
• When the master function is used, 'Master function error set signal' (X03) turns on and the error code is stored in 'Master
function error information' (Un\G433).
• When the slave function is used, 'Slave function error set signal' (X08) turns on and the error code is stored in 'Slave
function error information' (Un\G1537).
In this case, the transmit/receive data in the buffer memory is forcibly updated.
• When the DNTMRD or DNTSRD dedicated instruction is not executed in three sequence scans, the latest receive data is
stored in 'Master function receive data' (Un\G1792 to Un\G2047) or 'Slave function receive data' (Un\G2816 to Un\G2879).
• When the DNTMWR or DNTSWR dedicated instruction is not executed in three sequence scans, the data stored in 'Master
function transmit data' (Un\G2304 to Un\G2559) or 'Slave function transmit data' (Un\G3072 to Un\G3135) is transmitted to
the destination node.
3 DEDICATED INSTRUCTION
3.2 Precautions for Dedicated Instructions
3
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