Pointer (P); Special Register (Sd) - Mitsubishi Electric MELSEC Q Series Programming Manual

5 SEQUENCE INSTRUCTIONS FOR MOTION CPU

5.1.10 Pointer (P)

5.1.11 Special register (SD)

The pointer indicates the branch instruction (CJ, CALL) jump destination.
The pointer number assigned at the jump destination head is called the label.
X13
33
36
Label
P20
501
X17
723
726
(1) For pointer, P0 to P249 can be used without restriction.
(2) P255 always indicates END. It can be used as a jump destination of a CJ
instruction. It cannot be used as a jump destination of a single label or CALL
instruction.
(3) P252 and P370 to P378 are labels for start which indicate the head of the program.
Do not use them as a device of CJ instruction or CALL instruction. Even for only a
main program, do not omit P252. (refer to section 3.5.2)
As the same as special relay (SM), special register is a 16bit register which has
predetermined applications in the system. Do not use special register for temporary
memory.
(1) Turning the power OFF initializes this device.
(2) The special register number is expressed as a decimal.
5 - 8
Pointer
Jump to label
CJ P20
P20 (step 501)
when X13 turns ON.
Jump to END when
CJ P255
X17 turns ON.