
4.LADDER LANGUAGE B-63983EN/02
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(3) Instruction
For the types of functional instructions, see Subsection 2.1.6.
To input the instruction with relay symbols, use the soft keys of
the programmer.
(4) Parameters
Unlike the basic instructions, the functional instructions deal
with numeric values. Therefore, reference data values and
addresses storing data may be entered in their parameters. The
number of parameters and the meanings of those parameters
differ for each functional instruction.
(5) W1
W1 is the destination to which the functional instruction outputs
its operation result when that result can be represented by a one-
bit value, 0 or 1. The designer can freely decide the address of
W1. The meaning of W1 differs for each functional instruction.
Some functional instructions do not have the W1 output.
(6) Data to be processed
The data processed by the functional instructions is in two
formats - binary coded decimal (BCD) format and binary format.
Formerly, the PMC system handled numeric data mainly in the
BCD format. However, dealing with all numeric data in the
binary format is now recommended for the following reasons.
(a) The numeric data exchanged between NC and PMC (M, S,
T, and B codes) is in the binary format.
(b) The CPU carries out all numeric data operations in the
binary format. Therefore, if data is provided in the binary
format, the conversion between the BCD and binary formats
becomes unnecessary, thus speeding up the PMC processing.
(c) The use of binary format data allows you to handle a wider
range of numeric data while at the same time making it
easier to deal with negative numeric data. This leads to an
enhanced operation capability. In principle, binary numeric
data is handled in units of one byte (−128 to +127), two
bytes (−32,768 to +32,767), or four bytes (−2,147,483,648
to +2,147,483,647).
(d) When you enter numeric data using the CNC screen keys or
display numeric data on the CNC screen, you will
experience no inconvenience because binary numeric data
values are all set and displayed in the decimal format. It is
just that the data stored in the internal memory is written in
the binary format. You only need to exercise care when the
sequence program references memory. See item (7) for
examples of numeric data. For the reasons mentioned
above, all the functional instructions described in this
manual are designed to deal with binary data and handle
mainly binary data.