5 -4
The names and functions of the major operands:
Abbreviation
Name
Descriptions
S Source
The data of source (S) operand are only for reading and reference and will not be
changed with the execution of the instruction. If there are more than one source
operands, each operand will be identified by the footnote such as Sa and Sb.
D Destination
The destination (D) operand is used to store the result of operation. The original data
will be changed after operation. Only the coils and registers which are not write
prohibited can be the destination operand.
L
Length
Indicates the data size or the length of the table, usually are constants.
N Number
A constant most often used as numbers and times. If there are more than one
constant, each constant will be identified by the footnotes such as Na, Nb, Ns etc..
Pr Pointer
Used to point to a specific a block of data or a specific data or register in a table.
Generally the Pr value can be varied, therefore cannot be constant or input register.
(R3840~R3847)
CV
Current value
Used in T and C instruction to store the current value of T or C
PV
Set value
Used in T and C instructions for reference and comparison
T Table
A combination of a set of consecutive registers forms a table. The basic operation
units are word and double word. If there is more than one table, each table will be
identified by footnotes such as Ta, Tb, Ts and Td etc..
M Matrix
A combination of a set of consecutive registers forms a matrix. The basic operation
unit is bit. If there is more than one matrix, each matrix will be identified by footnotes
such as Ma, Mb, Ms and Md etc..
Besides the major operands mentioned above, there are other operands which are used for certain special purposes such
as the operand Fr for frequency, ST for stack, QU for Queue etc.. Please refer to the instruction descriptions for more
details.
The types of the operand and their range: The types of operand for the function instructions are discrete, register
and constant.
a) Discrete operand :
There are total five function instructions that reference the discrete operand, namely SET, RST, DIFU, DIFD
and TOGG. Those five instructions can only be used for operations of Y
(external output), M
(internal and special) and S
(step) relays. The table shown below indicates the operands and ranges of
the five function instructions.
Y
M
SM
S
Range
Ope-
rand
Y0
∣
Y255
M0
∣
M1911
M1912
∣
M2001
S0
∣
S999
D
○
○
○
*
○
Symbol "O" indicates the D (Destination operand) can use this type of
coils as operands. The "*" sign above the "O" shown in SM column
indicates that should exclude the write prohibited relays as operands.
Please refer to page I2-8 for introduction of the special relays.
b) Register operand :
The major operand for function instructions is register operand. There are two types of register operands: the
native registers which already is of Words or Double Words data such as R, D, T, C. The other is derivative
registers (WX, WY, WM, WS) which are formed by discrete bits. The types of registers that can be used as
instruction operands and their ranges are all listed in the following table:
