Campbell Scientific CR5000 Measurement and Control Module - Manual (Page 211)

Section 9. Program Control Instructions
9-5
Do
Repeats a block of statements while a condition is true or until a condition
becomes true.
Syntax 1
Do [{While | Until} condition]
[statementblock]
[Exit Do]
[statementblock]
Loop
Syntax 2
Do
[statementblock]
[Exit Do]
[statementblock]
Loop [{While | Until} condition]
The Do...Loop statement has these parts:
Part Description
Do Must be the first statement in a Do...Loop control structure.
While Indicates that the loop is executed while condition is true.
Until Indicates that the loop is executed until condition is true.
condition Numeric expression that evaluates true (nonzero) or false (0
or Null).
statementblock Program lines between the Do and Loop statements that are
repeated while or until condition is true.
Exit Do Only used within a Do...Loop control structure to provide an
alternate way to exit a Do...Loop. Any number of Exit Do
statements may be placed anywhere in the Do...Loop. Often
used with the evaluation of some condition (for example,
If...Then), Exit Do transfers control to the statement
immediately following the Loop. When Do...Loop
statements are nested, control is transferred to the Do...Loop
that is one nested level above the loop in which the Exit Do
occurs.
Loop Ends a Do...Loop.
Do...Loop Statement Example
The example creates an infinite Do...Loop that can be exited only if Volt(1) is
within a range.
Dim Reply 'Declare variable.
Do
Reply = Volt(1)
If Reply > 1 And Reply < 9 Then
'Check range.
Exit Do 'Exit Do Loop.
End If
Loop