3. INSTRUCTION STRUCTURE
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MELSEC-A
3.2 Bit Processing
Bit processing is performed when a bit device (X, Y, M, L, S, B, F) has been specified.
Either of 1-bit processing or digit specification processing with 16-bit or 32-bit
instructions may be selected.
3.2.1 1-bit processing
When the sequence instruction is used, more than one bit (one point) cannot be
specified for the bit device.
Example: LD X0, OUT Y20
3.2.2 Digit specification processing
When the basic and application instructions are used, the number of digits may need
to be specified for the bit device. Up to 16 points can be specified in 4 point
increments when a 16-bit instruction is used, and up to 32 points can be specified
when a 32-bit instruction is used.
(1) 16-bit instruction: K1 to 4 (4 to 16 points)
Example: Setting range by the digit specification of 16-bit data, X0 to F
Fig.3.1 Digit Specification Range of 16-Bit Instruction
(a) When there is digit specification on the source (S) side, the range of
numeric values handled as source data are as shown in Table 3.1.
Specified Number of Digits 16-Bit Instruction
K1 (4 points) 0 to 15
K2 (8 points) 0 to 255
K3 (12 points) 0 to 4095
K4 (16 points) −32768 to 32767
Specification range of K1
(4 points)
Specification range of K2
(8 points)
Specification range of K3
(12 points)
Specification range of K4
(16 points)
Table 3.1 List of Di
it S
ecification and Numeric Values
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