Delta RMC151 - Manual (Page 335)

5 Programming
Box Description
Time to Delay The Time to Delay specifies the number of seconds to wait before
jumping to the next step in the User Program. It must evaluate to a
numeric value and may be any of the following:
• Constant value
• Register
• Variable
• Numeric Expression
Jump To Specifies the step to jump to. It must be a valid step number, step
label, "Next", or "Repeat".
To select the Delay Link Type:
• Open or create a User Program.
• Go to the step where you want the Delay Link Type.
• Double-click the Link Type box.
• Click Delay.
Entering an Expression in the Delay Link Type
If you use an expression in the Delay Link Type, it must evaluate to a REAL value. To
enter an expression, double-click the Time to Delay box, which will open the Expression
Editor. The expression can be one line only. For more details on creating an expression,
see the Expressions Overview.
Example Time to Delay Expressions
Example 1
Example 2
Note: MyTimeToDelay must exist as a variable.
Timing Considerations
After the step containing the Delay link type is executed, the RMC will wait the specified
number of seconds, then jump to the next step and execute it. Therefore, the next step
will be executed exactly at the delay time plus one loop time after the first step.
For example, consider a program where step 0 contains the Delay link type with a time of
0.1 seconds and jumps to the next step. Assume the controller loop time is set to 0.001
seconds (1000 µs). If step 0 is executed at time 0 (zero), then step 1 will be executed at
time 0 + 0.1 + 0.001, which is 0.101.
If you want the step to be executed at a specific interval, you must specify the delay to
be the interval time minus the loop time. For example, if you wish to issue the commands
at exactly a 2 second interval and the loop time is 0.0005 seconds (500 µsec), you should
set the delay time to 1.9995 seconds.
You can use the _LoopTime tag to specify get the loop time. The _LoopTime tag is
accessible from the Expression Builder on the Tags tab, in the Controller section.
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