3.1 Basic Functionality
3.1.2 Registers
3-21
3
CPU Module Functionality
•
Setting the D Register Clear When Start Option
1.
Select
File
−
Environment Setting
from the MPE720 Version 7 Window.
2.
Select
Setup
−
System Setting
.
3.
Select
Enable
or
Disable
for the
D Register Clear when Start
option.
Disable: The initial values will be uncertain.
Enable: The initial values will be 0.
Data Types
There are various data types that you can use depending on the purpose of the application: bit,
integer, double-length integer, quadruple-length integer, real number, double-precision real
number, and address.
D registers
When the function is called, the previously set values are preserved.
If a previous value is not necessary, initialize the value, or use a Z register instead.
D registers retain the data until the power is turned OFF.
The default value after startup depends on the setting of the
D Register Clear when
Start
option.
Refer to the following sections for details.
Setting the D Register Clear When Start Option
Symbol
Data Type
Range of Values
Data Size
Description
B
Bit
1 (ON) or 0 (OFF)
−
Used in relay circuits and to
determine ON/OFF status.
W
Integer
-32,768 to 32,767
(8000 to 7FFF hex)
1 word
Used for numeric operations.
The values in parentheses on
the left are for logical opera-
tions.
L
Double-length
integer
-2,147,483,648 to 2,147,483,647
(80000000 to 7FFFFFFF hex)
2 words
Used for numeric operations.
The values in parentheses on
the left are for logical opera-
tions.
Q
Quadruple-
length integer
*1
-9,223,372,036,854,775,808 to
9,223,372,036,854,775,807
(8000000000000000 to
7FFFFFFFFFFFFFFF hex)
4 words
Used for numeric operations.
The values in parentheses on
the left are for logical opera-
tions.
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Name
Precautions
