Specifications

56 RSLinx – Training Guide
The following information is displayed in the Alias Topic Configuration
dialog box:
• List of Alias Topics shows a list of configured alias topics.
If a topic is active and is selected, all configuration items for that topic will be
grayed out.
•
Alias Name is the reference to the alias topic.
•
Available Topics shows a list of device topics available for the alias topic.
Once an aliased topic is used, only matching topics will be displayed.
•
Aliased Topics shows a list of topics in the order to be switched to on
configured switch parameters.
•
Switch on Error tells the alias topic that any error that occurs on the topic
causes an immediate switch to the next topic in the aliased topic list. If it is
presently active on the last topic, it switches back to the beginning.
•
Switch on Command tells the alias topic to allow a DDE Execute to switch
the topic to the next or another topic.
•
Switch when bit is (either “zero” or “one” are the options) tells the alias topic
that if the watched bit goes to zero, switch the alias topic to the next aliased
topic (see Switch on error).
EXAMPLE: Set the active DDE topic configured in an alias topic
This example displays how to programmatically set the active DDE topic that is
configured in an alias topic using Microsoft Excel VBA.
RSIChan = DDEInitiate("RSLinx", "System")
Application.DDEExecute RSIChan, "[Set_Alias(My_Alias,KT_Topic)]"
where:
• RSLinx is the DDE application name.
• System is a predefined topic of RSLinx.
• My_Alias is the user configured alias name in RSLinx.
• KT_Topic is the DDE topic that RSLinx switches to