Macros and multi-tasking

FactoryTalk View

has multi-tasking capabilities that you can take advantage of when you create macros. Generally, the commands in a macro are run in the order in which they are listed; one command ends before the next begins execution.

Some commands (such as

Print

) finish quickly and the next command can start. Other commands, such as

Set

, take longer.

Set

does not finish until the message goes to the programmable controller. In cases like this, set up the macro so that the next command can be run before the previous command finishes. Use the ampersand character (

&

) to do this.

For example, to have a command immediately following a

Set

command start before the

Set

command finishes, place an

&

(ampersand character) in front of the

Set

command.

The timing of commands can also be an issue where a command sets something in motion that needs to end before the subsequent command can be run. This occurs most commonly with the

Display

command where a subsequent command is intended to act on objects in the display. In such cases, the next command will attempt to run although the objects in the display might not yet be initialized. For example, if you use the

Invoke

command to run a method on an

ActiveX

object in a display, the

Invoke

command will fail if the object is not yet initialized. You can use the

Pause

command to give the objects in the display time to initialize before the next command is given.