Configuration Of Instructions - Mitsubishi MELSEC Q Series Programming Manual

3.1

Configuration of Instructions

Most CPU module instructions consist of an instruction part and a device part.
Each part is used for the following purpose:
• Instruction part ...... indicates the function of the instruction.
• Device part ............ indicates the data that is to be used with the instruction.
The device part is classified into source data, destination data, and number of devices.
(1) Source (S)
(a) Source is the data used for operations.
(b) The following source types are available, depending on the designated device:
(2) Destination (D)
(a) The destination stores the data after the operation has been conducted. However,
(b) A device for the data storage must always be set to the destination.
(3) Number of devices and number of transfers (n)
(a) The number of devices and number of transfers designate the numbers of devices and
(b) The number of devices or number of transfers can be set between 0 and 32767.
3-2
• Constant ............................................... Designates a numeric value to be used in the
• Bit devices and word devices ............... Designates the device that stores the data to
some instructions require storing the data to be used in an operation at the destination
prior to the operation execution.
Example
An addition instruction involving BIN 16-bit data
+ S
Stores the data needed for operation
before the actual operation.
transfers used by instructions involving multiple devices.
Example
Block transfer instruction
However, if the number is 0, the instruction will be a no-operation instruction.
operation.
This is set when the program is created, and
cannot be changed during the execution of
the program.
Constants should be indexed when used as
variable data.
be used in the operation.
Data must be stored in the designated
device until the operation is executed.
By changing the data stored in a designated
device during program execution, the data to
be used in the instruction can be changed.
D
BMOV S D
n
Designates the number of transfers
used by a BMOV instruction
+ S1 S2 D
Stores only the
operation results.