Mitsubishi Electric MELSEC-Q Series Programming Manual page 98

Item
When the specified block is
active:
• When multiple initial steps exist, an initial step selection START will occur when a given step is specified and activated.
• When designating a step located in a parallel branch, all the parallel steps should be activated. An inactive parallel branch
ladder at such a time will prevent the parallel coupling condition from being satisfied.
• If a specified step is already active when this instruction is executed, the instruction will be ignored (equivalent to the NOP
instruction), and processing will continue. To hold a specified step with the HOLD step, the processing is "Transition to
HOLD step by double START". For details, refer to Page 127 Operation mode at transition to active step (double step
START).
• When the operation output is used to start the step, do not specify the current step number as the specified step number. If
the current step is designated as the specified step number, normal operation will not be performed.
• Specify the step as described below.
Item
In the case of SFC program
In the case of sequence program
• While online change (inactive block) is executed to the specified block when this instruction is executed, the instruction will
be ignored (equivalent to the NOP instruction), and the online change processing will continue. (Universal model QCPU
whose serial number (first five digits) is "12052" or later, and the LCPU whose serial number (first five digits) is "15102" or
later only)
4 SFC PROGRAM CONFIGURATION
96
4.4 Controlling SFC Programs by Instructions (SFC Control Instructions)
Description
If the step is already active when the SET instruction is executed, the step will remain active and processing will continue, with
another step being designated as active. (Multiple step activation, follow-up function.)
Processing is performed as shown below when step 1 in block 1 is started in the sequence program.
Description
Use "Sn" when specifying the step in the current block.
Use "BLm\Sn" when specifying the step in another block.
Use "BLm\Sn" when executing the step START instruction in the sequence program.
When the block number is not specified, specify the block number with the BRSET instruction. Note, however, 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