11 - 257 11 - 257
MELSEC-Q
11 INSTRUCTIONS AND FUNCTIONS
• <Storage area for data to be written> is a variable or device range that stores the
data to be written to the PLC CPU. Specify an integer variable, integer array name,
character variable, character array variable, extension registers ED, or extension
relays EM.
Each of them is specified in the following manner.
Integer variable
%
Character variable
$
Integer array name
% ( )
Character array variable
$ (n)
ED
W@ (ED,n)
Expressed by special variables.
EM
B@ (EM,n)
An array used as <storage area for data to be written> must always be defined using
the DIM instruction, even if the number of elements used is 10 or less.
An error occurs if the PCWT instruction is executed without defining the array.
(Usually, an array with 10 or fewer elements can be used without defining it with
the DIM instruction.)
• See Section 4.2.6 for how to store data written.
• Some of the processing that can be performed by the PCWT instruction is not
possible to execute if the relevant PLC CPU is running. The following message is
shown in the descriptions below if the processing cannot be executed while the PLC
CPU is running:
Processing Disabled while Running
Be sure to reset the AD51H once if the type of the PLC CPU in the data link system
that is being accessed from the AD51H is changed.
Incorrect data may be written if it is attempted to access
the PLC CPU without resetting it.
