Note:
Each condition must be placed in parentheses for proper evaluation by the RIO. In addition, the
RIO executes operations from left to right.
For example, using variables named V1, V2, V3 and V4:
JP #TEST, (V1<V2) & (V3<V4)
In this example, this statement will cause the program to jump to the label #TEST if V1 is less than V2
and V3 is less than V4. To illustrate this further, consider this same example with an additional
condition:
JP #TEST, ((V1<V2) & (V3<V4)) | (V5<V6)
This statement will cause the program to jump to the label #TEST under two conditions: 1) If V1 is
less than V2 AND V3 is less than V4. OR 2) If V5 is less than V6.
Using the JP Command:
If the condition for the JP command is satisfied, the RIO branches to the specified label or line
number and continues executing commands from this point. If the condition is not satisfied, the RIO
board continues to execute the next commands in sequence.
Instruction
Interpretation
JP #Loop,COUNT<10
Jump to #Loop if the variable, COUNT, is less than 10
JS #MOVE2,@IN[1]=1
Jump to subroutine #MOVE2 if input 1 is logic level high. After the
subroutine MOVE2 is executed, the program sequencer returns to the
main program location where the subroutine was called.
JP #BLUE,@ABS[V2]>2
Jump to #BLUE if the absolute value of variable, V2, is greater than 2
JP #C,V1*V7<=V8*V2
Jump to #C if the value of V1 times V7 is less than or equal to the value
of V8*V2
JP#A
Jump to #A
Using If, Else, and Endif Commands
The RIO provides a structured approach to conditional statements using IF, ELSE and ENDIF
commands.
Using the IF and ENDIF Commands
An IF conditional statement is formed by the combination of an IF and ENDIF command. The IF
command has arguments of one or more conditional statements. If the conditional statement(s)
evaluates true, the command interpreter will continue executing commands which follow the IF
command. If the conditional statement evaluates false, the RIO will ignore commands until the
associated ENDIF command is executed OR an ELSE command occurs in the program (see discussion
of ELSE command below).
Note:
An ENDIF command must always be executed for every IF command that has been executed.
Using the ELSE Command
The ELSE command is an optional part of an IF conditional statement and allows for the execution of
commands only when the argument of the IF command evaluates False. The ELSE command must
occur after an IF command and has no arguments. If the argument of the IF command evaluates
false, the RIO will skip commands until the ELSE command. If the argument for the IF command
evaluates true, the RIO board will execute the commands between the IF and ELSE commands.
Chapter 5 Programming ▫ 63 RIO-47xxx Rev 1.0r