Section 7. Installation
165
Using TRUE or FALSE conditions with logic operators such as AND and OR,
logical expressions can be encoded to perform one of the following three general
logic functions. Doing so facilitates conditional processing and control
applications:
1. Evaluate an expression, take one path or action if the
expression is true (=
–1),
and / or another path or action if the expression is false (= 0).
2. Evaluate multiple expressions linked with
AND
or
OR
.
3. Evaluate multiple
AND
or
OR
links.
The following commands and logical operators are used to construct logical
expressions.
TABLE: Logical Expression Examples
(p. 165)
demonstrate some
logical expressions.
•
IF
•
AND
•
OR
•
NOT
•
XOR
•
IMP
•
IIF
Logical Expression Examples
If X >= 5 then Y = 0
Sets the variable Y to 0 if the expression "X >= 5" is true, i.e. if X is greater than or equal to 5. The
CR800 evaluates the expression (X >= 5) and registers in system memory a
-1
if the expression is true, or
a
0
if the expression is false.
If X >= 5 OR Z = 2 then Y = 0
Sets Y = 0 if either X >= 5 or Z = 2 is true.
If X >= 5 AND Z = 2 then Y = 0
Sets Y = 0 only if both X >= 5 and Z = 2 are true.
If 6 then Y = 0.
If 6
is true since
6
(a non-zero number) is returned, so Y is set to
0
every time the statement is executed.
If 0 then Y = 0.
If 0
is false since
0
is returned, so Y will never be set to
0
by this statement.
Z = (X > Y).
Z equals
-1
if X > Y, or Z will equal
0
if X <= Y.
Summary of Contents for CR800 Series
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Page 446: ...Section 8 Operation 446 8 11 2 Data Display FIGURE 100 CR1000KD Displaying Data ...
Page 448: ...Section 8 Operation 448 FIGURE 102 CR1000KD Real Time Custom ...
Page 449: ...Section 8 Operation 449 8 11 2 3 Final Storage Data FIGURE 103 CR1000KD Final Storage Data ...
Page 450: ...Section 8 Operation 450 8 11 3 Run Stop Program FIGURE 104 CR1000KD Run Stop Program ...
Page 452: ...Section 8 Operation 452 FIGURE 106 CR1000KD File Edit ...
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