Specifications

A - 16 RSLinx – Training Guide
Communication Status Information:
In RSLinx when using DDE/OPC there are diagnostic tools for troubleshooting
communications problems. The Active Items List shows the addresses currently
being requested by RSView32. The Communication Event Log shows the last
500 errors, and the affected item in the list. The Optimized Packets shows how
RSLinx is optimizing the data requested by RSView32, and shows the number of
packets received, how many are valid, and how many are invalid. Client and
Server Diagnostics can be referenced for additional information.
In RSView32, there exists some communication status tags that can be
referenced for trouble shooting communications problems. These tags are only
updated when an application is referencing them. So in other words, if the tags
are read after a communication error they are uninitialized. For this reason, it is a
good idea to create a datalog model - which only logs on demand - for these
system tags. This will keep the tags current and fresh by continually referencing
them. A list of these tags follows...
When channels are configured in RSView32, the following 4 system tags are
created for each channel. Here channel 1 has been configured for DH+.
System\ComErrorString1 - the last error that occurred
System\ComErrorValue1 - the last error number that occurred
System\ComStatusString1 - the current status, usually Success - no error.
System\ComStatusValue1 - the current status number, 0 = success no error
When a DDE node is created in RSView32, the following 4 system tags are
created.
System\ComErrorStringDDE
System\ComErrorValueDDE
System\ComStatusStringDDE
System\ComStatusValueDDE