Mitsubishi Electric MELSEC-Q Series Programming Manual page 79

Function
• Checks a specified step in a specified block to determine if the step is active or inactive.
• The contact status changes as described below depending on whether the specified step is inactive or active.
Inactive
Active
• Specify the step as described below.
Item
In the case of SFC program
In the case of sequence program
*1 Note that the following CPU modules cannot use the BRSET instruction. When no block number is specified, the block 0 is set.
 Basic model QCPU
 Universal model QCPU whose serial number (first five digits) is "13101" or earlier
 LCPU
• If the step does not exist in the SFC program is specified, the contact remains OFF.
• As the "Sn" device is treated as a virtual device, the contact on the monitor of a peripheral device does not
turn ON/OFF. If the internal device is ON, the coil instruction is switched ON for operations.
• In the High-speed Universal model QCPU, the number of steps in the step activation check instruction
increases by one step from that in the QnUDE(H)CPU.
Program example
• The following program checks the status of step 5 in block 3 and turns ON Y20 when step 5 becomes active.
When step is designated by operation output of block 3
When step is designated by operation output of other than block 3
When step is designated by sequence program
Contact of N/O Contact Instruction
OFF
ON
Description
Use "Sn" when specifying the step in the current block.
Use "BLm\Sn" when specifying the step in another block in the SFC program.
Use "BLm\Sn" when executing the step activation check instruction.
When the block number is not specified, specify the block number with the BRSET instruction.
4.4 Controlling SFC Programs by Instructions (SFC Control Instructions)
Contact of N/C Contact Instruction
ON
OFF
*1
4 SFC PROGRAM CONFIGURATION
4
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