Refresh - Mitsubishi Electric MELSEC-Q/L Programming Manual

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Refresh

Refer to Page 489 Select refresh (COM) for the COM instruction of the following CPU modules.

• Basic model QCPU of serial No. 04122 or later

• High Performance model QCPU of serial No. 04012 or later

• Process CPU of serial No. 07032 or later

• Redundant CPU

• Universal model QCPU

Internal device

Processing details

• Use the COM instruction for the following purposes.

• To reduce the time required to send/receive data to/from the remote I/O stations.

• To ensure data communication with a CPU module on another station when two CPU modules perform operations using different scan times.

• The processing of the COM instruction differs depending on the status (ON or OFF) of the special relay SM775.

• SM775 is OFF: Performs both auto refresh and communication with external devices.

• SM775 is ON: Performs only communication with external devices.

*1 The following processing is performed in communication with external devices.

• Monitor processing of other station

• Read processing by the serial communications module of the buffer memory of another intelligent function module

*2 The auto refresh includes the following processing:

• Refresh of MELSECNET/10, MELSECNET/H

• CC-Link refresh

• Auto refresh of intelligent function modules

• At the point of the execution of the COM instruction, the CPU module temporarily stops the processing of the sequence

program, and performs the same operation as ordinary data processing as well as auto refresh of intelligent function

modules (including link refreshes) at the END processing. However, the low speed cyclic refresh of MELSECNET/10 or

MELSECNET/H is not performed.

Execution of COM instruction

• The COM instruction can be used in a sequence program any number of times. Note, however, that the scan time of the

sequence program will increase by the time taken for communication with external devices and auto refresh (including link

refresh) of intelligent function modules.

Execution of COM instruction

General data processing and auto refresh

(including link refresh) of intelligent function module

7 APPLICATION INSTRUCTIONS

7.6 Structure Creation Instructions