Special Variables (How To Use B@ And W@) - Mitsubishi QD51 Programming Manual

2 THE BASICS OF AD51H-BASIC

2.8.3 Special variables (How to use B@ and W@)

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• These variables are used to read/write from/to each device of the communication
module from within BASIC programs.
• There are the following 4 types of special variables.
B@ (EM, expression)
W@ (ED, expression)
B@ (X, expression)
W@ (Y, expression)
Refer to the user's manual for each communication module for details on the extension
relays EM, extension registers ED, general-purpose inputs X, and general-purpose
outputs Y.
Note that it is possible to read and write to/from the special EM and special ED
extension devices.
(1) Reading from and writing to bit devices
B@(EM, expression)
B@(X, expression)
B@(Y, expression)
• Specify a device number in the expression.
When general-purpose inputs X or outputs Y are specified, values between 0
and1F are used regardless of the input/output numbers of the entire system.
H
A
X
The input/output
41
numbers as seen (32 points)
0 to 1F
from the PLC CPU
Value specified
in the expression
• • • • • Read/write from/to the extension relays EM.
• • • • • Read/write from/to the registers ED.
• • • • • Write to general-purpose inputs X.
• • • • • Read from general-purpose outputs Y.
• • • • • Specify a value between 0 and 1023 for
the expression.
Specify a value between 0 and 1F
expression. Since this must be specified in
• • • • •
hexadecimal, place '&H' in front of the
numeric value.
A AD A A
X 51 X Y
41 H 41 41
(32 points) (48 points) (32 points) (32 points)
• • • •
20 to 3F 40 to 6F 70 to 8F 90 to AF B0 to CF
40
to 4F 50 to 6F
?
General-purpose
inputs/outputs
?
X, Y
0 to 1F
MELSEC-Q
A A
Y Y
41 41
(32 points) (32 points)
• •
D0 to EF
for the
H
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