146
FX
3U
/FX
3UC
Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
6 What to Understand before Programming
6.5 General Rules for Applied Instructions
6.5
General Rules for Applied Instructions
6.5.1
Expression and operation type of applied instructions
Instructions and operands
- To applied instructions in PLCs, function numbers FNC 00 to FNC
are assigned. A symbol
(mnemonic) indicating the contents is given to each instruction.
For example, a mnemonic "SMOV (shift move)" is assigned to FNC 13 instruction.
- Some applied instructions function only with their instruction part, but many instructions consist of the
instruction part and following operands.
: An operand whose contents do not change by execution of the instruction is called
"source", and indicated by this symbol.
When a device number can be indexing with index registers, the source is expressed as
with addition of "
".
When there are two or more sources, they are expressed as
,
, etc.
: An operand whose contents change by execution of the instruction is called "destination",
and indicated by this symbol.
When indexing is allowed and there are two or more destinations, they are expressed as
,
, etc. in the same way as source.
m, n
: Operands not falling under source or destination are expressed as m and n.
When indexing is allowed and there are two or more such operands, they are expressed as
m1
, m2
, n1
, n2
,etc. in the same way as source and destination.
- In applied instructions, the program step of the instruction part always occupies 1 step, but each
operand occupies 2 or 4 steps depending on whether the instruction is 16-bit type or 32-bit type.
Devices handled as operands
- Bit devices themselves such as X, Y, M and S may be handled.
- Combined bit devices, KnX, KnY, KnM, KnS, etc, may be handled as numeric value data.
→
Refer to Section 5.4.
- Data registers D and current value registers for timers T and counters C may be handled.
- Though data registers D are the 16-bit type, two serial data registers are combined when 32-bit data is
handled.
For example, when a data register D0 is specified as an operand in a 32-bit instruction, D1 and D0 are
combined to handle 32-bit data. (D1 handles high-order 16 bits, and D0 handles low-order 16 bits.)
When current value registers for T and C are used as general data registers, they are handled in the
same way.
However, each of 32-bit counters C200 to C255 can handle 32-bit data, and cannot be specified as an
operand in a 16-bit instruction.
Command
input
FNC 13
SMOV
S
D
n
m1
m2
S
S
S
1
S
2
D
D
1
D
2
