Chapter 2 Structure And Combinations Of Process Control Instructions; Structure Of Instructions - Mitsubishi MELSEC-Q series Programming Manual

CHAPTER 2
2.1

Structure of Instructions

The instructions that can be used by the process control instructions can be divided into the "instruction part" and "device
part".
The instruction part and device part are as follows.
• Instruction part.......This shows the functions for these instructions.
• Device part.............This shows the data required for operations and the storage destination of the stored operation results.
The device part is classified as the source device and destination device.
(1) Source (S)
The source stores the data used for operation.
(a) In the process control instruction, specify the head device that stores the source data.
(b) Data must have been stored in the specified device until the process control instruction is executed.
(c) Changing the source data allows you to change the data used in that instruction.
(2) Destination (D)
Destination is where the data is stored after operation.
(a) Sets the device for which the data will be stored in the destination.
(b) Depending on the instruction used, data used for operation must also be stored in the destination before start of the
operation.
For the structure of instructions used in structured programs, refer to the MELSEC-Q/L Structured Programming Manual
(Common Instructions).
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STRUCTURE AND COMBINATIONS OF
PROCESS CONTROL INSTRUCTIONS