Using Generic OPC server network in CHMI 800
If use "Generic OPC server network" in my CHMI 800, how to get alarm and event of OPC item?
I can't find where is alarm setting.
Voted best answer
The most reliable method is to make use of the source's OPC AE server and configure an 800xA Event Collector group to retrieve A&E via OPC AE interface. Certain rules apply; e.g. will you have to pre-create objects that should "own" the alarm; or else Lost & Found folder will be populated for each missing object.
If the source does not have OPC AE interface; the alternative is to make use of PLC Connects AE feature with which you can raise an alarm based on some level, etc. that you program into the PLC Connect object using the Alarm Event Configuration aspect. This is described in the PLC Connect User's Guides.
The last option (which I do not promote) is to make use of regular Alarm Expressions to create alarms. Alarm Expressions is mentioned in the 800xA Configuration User's
Due to the nature of Alarm Expressions (they need OPC DA feed...) no alarm will be raised if the feed is interrupted. System diagnostic alarms will be raised if an Alarm Expression receives bad quality on input, however, in some situations (unreliable feed from OPC server) the system might be flooded with diagnostic alarms to the degree that you become forced to turn them off. In that case; you will have no alarm if OPC DA feed is interrupted, nor will any diagnostic alarm fire to warn you about this.
The very best option is to retrieve alarms from a bona fide OPC AE server associated with the source.