Campbell-scientific CR3000 Micrologger Manuale Utente Pagina 151

  • Scaricare
  • Aggiungi ai miei manuali
  • Stampa
Vedere la pagina 150
Section 7. Installation
151
TRUE is safe, it may not always be the best programming technique. Consider the
expression
If Condition(1) then...
Since = True is omitted from the expression, Condition(1) is considered true if it
equals any non-zero value.
Table 21. Binary Conditions of TRUE and FALSE
Condition
CRBasic Instruction(s)
Used
Memory Location of Binary
Result
Time
TimeIntoInterval()
Variable, System
IfTime()
Variable, System
Control Port Trigger
WaitDigTrig()
System
Communications
VoiceBeg()
System
ComPortIsActive()
Variable
PPPClose()
Variable
Measurement Event
DataEvent()
System
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. CRBasic example Logical Expression Examples
(p. 151) demonstrate
some logical expressions.
IF
AND
OR
NOT
XOR
IMP
IIF
Table 22. 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 CR3000 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.
Vedere la pagina 150
1 2 ... 146 147 148 149 150 151 152 153 154 155 156 ... 589 590

Commenti su questo manuale

Nessun commento