How to fetch Event time of an alarm/event to graphics
Hi all,
There is an requirement to show the list of all trip conditions & further in case of trip the sequence/order of events in graphics.
1. Is there any way we can fetch the event time of individual tags to graphics?
2. If option 1 not possible, is there a way to create dedicated events (To avoid duplication in any other event list)
3. How to freeze & store the date&time in graphics ( This is to avoid continuous subscription of data from OPC & so to reduce load)
There is an requirement to show the list of all trip conditions & further in case of trip the sequence/order of events in graphics.
1. Is there any way we can fetch the event time of individual tags to graphics?
2. If option 1 not possible, is there a way to create dedicated events (To avoid duplication in any other event list)
3. How to freeze & store the date&time in graphics ( This is to avoid continuous subscription of data from OPC & so to reduce load)
Asked 3 months ago
Voted best answer
2
With System 800xA, there exist no standard method to retrieve OPC AE event timestamps via OPC DA for use in e.g. process graphics.
Event lists have time info but does not allow you to home in on any particular event, the last occured with be on top or bottom of the list depending on sort order. An event list can be embedded into PG2 using an aspect view wrapper (with some penalty in callup time/performance since you are actually calling a merge of two different aspects).
If only a few objects need this function, maybe you can clamp the event time in the controller and fetch it via OPC DA?
A calculation can be set to trigger on an OPC DA data change; the calculation can store the time it become triggered into a lab log (search AKS for examples I've posted) but there will be a latency since the delivery of data from PLC to calculation may take a second or two.
Event lists have time info but does not allow you to home in on any particular event, the last occured with be on top or bottom of the list depending on sort order. An event list can be embedded into PG2 using an aspect view wrapper (with some penalty in callup time/performance since you are actually calling a merge of two different aspects).
If only a few objects need this function, maybe you can clamp the event time in the controller and fetch it via OPC DA?
A calculation can be set to trigger on an OPC DA data change; the calculation can store the time it become triggered into a lab log (search AKS for examples I've posted) but there will be a latency since the delivery of data from PLC to calculation may take a second or two.
Answers
2
1. No. Tags don't have a date/time. Event Messages have a Timestamp. Tags can have multiple Messages.
2. Events are not sent to lists. There is only ONE event. Multiple lists can ( and do) show the same Event. If you see the same Event in two different lists then you're looking at the SAME event.
3. You can't. Graphics show real time data. Events are logged in a database, but can only be accesses via Event Lists or an OPC-AE subscription.
So what can you do ? ...
1. Create A Generic Object called "Trip List" in the Alarm Structure
2. Insert (not create) the existing Objects under the new Trip List object that you want to include in the "Trip List" Alarm List
3. Create an Alarm List and Event List aspect in the "Trip List" object that shows Objects and Descendants in the "Alarm Structure"
4. Add a Page Link, Alarm Band, or your preferred way of opening or viewing the Trip List.
2. Events are not sent to lists. There is only ONE event. Multiple lists can ( and do) show the same Event. If you see the same Event in two different lists then you're looking at the SAME event.
3. You can't. Graphics show real time data. Events are logged in a database, but can only be accesses via Event Lists or an OPC-AE subscription.
So what can you do ? ...
1. Create A Generic Object called "Trip List" in the Alarm Structure
2. Insert (not create) the existing Objects under the new Trip List object that you want to include in the "Trip List" Alarm List
3. Create an Alarm List and Event List aspect in the "Trip List" object that shows Objects and Descendants in the "Alarm Structure"
4. Add a Page Link, Alarm Band, or your preferred way of opening or viewing the Trip List.
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