Are there Point Link (pointLink) tutorials, or examples?

AldoRamos

I've been having a problem with a point link, and having a tough time finding any documentation specific to Point Links (hence spelling it both ways in the subject line and tags)

I believe the target point is set by

return source.value;

rather than explicitly calling

target.set(source.value);

but I haven't found it explicitly stated anywhere.

Finally, the real problem I am experiencing is that the point link appears not to set the target no matter what I do, but it has worked in the past, so I am trying to best understand what the problem might be.

Thanks,

Aldo

phildunlap

Hi Aldo,

You are correct, it should indeed be returned via return source.value (but if your script is that simple you need not have one (a point link with an empty script just sets the value simply)).

However, the ability to call set() was added to all scripting environments, so target.set(source.value); should also work (Note that you will need script permissions configured on the point link to set points)

We did fix a NullPointerException fairly recently related to Point Links. It's possible your point link is configured not to set the annotation, but that null pointer is what is causing you not to see the value. If so, I would say try setting the annotation again or updating to the latest.

Other conditions would produce a point link failure event that you could see in your events table.

Edit: And you mean, "appears not to set the target," correct?

AldoRamos

Correct on the typo; I've fixed it.

AldoRamos

I don't see any NullPointerException in the log, but I do occasionally get:

FATAL 2017-10-19 13:28:05,674 (com.serotonin.m2m2.util.timeout.RejectedHighPriorityTaskEventGenerator.rejected:47) - High priority task: com.serotonin.m2m2.rt.dataImage.DataPointRT rejected because Task Currently Running

This doesn't appear to correlate with attempts to execute the point link, but it's the only error message I am seeing, so I have to wonder.

AldoRamos

Also, the empty script was implied in the documentation, but I wasn't certain (especially given the problems we are experiencing with point links)

AldoRamos

And FWIW, this is running core 2.8.8 build 635, pointLinks 1.6.0

phildunlap

Hmm. That rejected task would probably be an interval logging task for a data point, but that would still enable the cache to have the result of the point link set.

The NullPointerException may have been escaping to stderr, I can't recall, or if it was logged as an uncaught task exception. If you point link doesn't set the annotation this could very likely cause it. target.set() wouldn't be an option in 2.8.8

You also checked your events and didn't have any cause?

"Disabled" isn't checked on your point link, is it?

AldoRamos

I do have it set to write annotation (and I have toggled it on & off several times in attempts to debug). Now that I think about it, I never see any annotations (except for manual set values), as expected given the behavior.

"Disabled" is not set (I wish it was a simple idiot mistake like that), although I have toggled it in attempts to debug.

phildunlap

I have tested the version you are on, it works as I expect (and is not affected by the annotation issue I believe, or that's only if you've got a websocket open to the target point perhaps).

Here is my configuration:

{
   "dataSources":[
      {
         "xid":"DS_808993",
         "name":"PL_TEST",
         "enabled":true,
         "type":"VIRTUAL",
         "alarmLevels":{
            "POLL_ABORTED":"URGENT"
         },
         "purgeType":"YEARS",
         "updatePeriodType":"MINUTES",
         "updatePeriods":1,
         "editPermission":"",
         "purgeOverride":false,
         "purgePeriod":1
      }
   ],
   "dataPoints":[
      {
         "xid":"DP_479771",
         "name":"Source",
         "enabled":true,
         "loggingType":"INTERVAL",
         "intervalLoggingPeriodType":"MINUTES",
         "intervalLoggingType":"AVERAGE",
         "purgeType":"YEARS",
         "pointLocator":{
            "dataType":"NUMERIC",
            "changeType":{
               "type":"NO_CHANGE",
               "startValue":"50"
            },
            "settable":true
         },
         "eventDetectors":[
         ],
         "plotType":"SPLINE",
         "unit":"",
         "templateXid":"Numeric_Default",
         "chartColour":"black",
         "chartRenderer":{
            "type":"IMAGE",
            "timePeriodType":"DAYS",
            "numberOfPeriods":1
         },
         "dataSourceXid":"DS_808993",
         "defaultCacheSize":1,
         "deviceName":"PL_TEST",
         "discardExtremeValues":false,
         "discardHighLimit":1.7976931348623157E308,
         "discardLowLimit":-1.7976931348623157E308,
         "intervalLoggingPeriod":1,
         "intervalLoggingSampleWindowSize":0,
         "overrideIntervalLoggingSamples":false,
         "purgeOverride":false,
         "purgePeriod":1,
         "readPermission":"",
         "setPermission":"",
         "textRenderer":{
            "type":"ANALOG",
            "useUnitAsSuffix":true,
            "unit":"",
            "renderedUnit":"",
            "format":"0.00"
         },
         "tolerance":0.0
      },
      {
         "xid":"DP_393152",
         "name":"Target",
         "enabled":true,
         "loggingType":"INTERVAL",
         "intervalLoggingPeriodType":"MINUTES",
         "intervalLoggingType":"AVERAGE",
         "purgeType":"YEARS",
         "pointLocator":{
            "dataType":"NUMERIC",
            "changeType":{
               "type":"NO_CHANGE",
               "startValue":"10"
            },
            "settable":true
         },
         "eventDetectors":[
         ],
         "plotType":"SPLINE",
         "unit":"",
         "templateXid":"Numeric_Default",
         "chartColour":"black",
         "chartRenderer":{
            "type":"IMAGE",
            "timePeriodType":"DAYS",
            "numberOfPeriods":1
         },
         "dataSourceXid":"DS_808993",
         "defaultCacheSize":1,
         "deviceName":"PL_TEST",
         "discardExtremeValues":false,
         "discardHighLimit":1.7976931348623157E308,
         "discardLowLimit":-1.7976931348623157E308,
         "intervalLoggingPeriod":1,
         "intervalLoggingSampleWindowSize":0,
         "overrideIntervalLoggingSamples":false,
         "purgeOverride":false,
         "purgePeriod":1,
         "readPermission":"",
         "setPermission":"",
         "textRenderer":{
            "type":"ANALOG",
            "useUnitAsSuffix":true,
            "unit":"",
            "renderedUnit":"",
            "format":"0.00"
         },
         "tolerance":0.0
      }
   ],
   "pointLinks":[
      {
         "xid":"PL_112332",
         "sourcePointId":"DP_479771",
         "targetPointId":"DP_393152",
         "event":"CHANGE",
         "logLevel":"NONE",
         "disabled":false,
         "script":"return source.value",
         "scriptPermissions":{
            "customPermissions":"",
            "dataPointReadPermissions":"superadmin",
            "dataPointSetPermissions":"superadmin",
            "dataSourcePermissions":"superadmin"
         },
         "writeAnnotation":true
      }
   ],
   "watchLists":[
      {
         "xid":"WL_908992",
         "name":"(unnamed)",
         "user":"admin",
         "dataPoints":[
            "DP_479771",
            "DP_393152"
         ],
         "data":null,
         "editPermission":null,
         "folderIds":null,
         "params":null,
         "query":null,
         "readPermission":null,
         "type":"static"
      }
   ]
}

Is it possible that you've pointed the link at a point that doesn't support setting, or that its device is failing the set so the value doesn't change?

AldoRamos

The target is a virtual data point (user input) so no device to fail. And I did check the "Settable" parameter. Several times. ;-)

My configuration is essentially identical to what you shared.

As I mentioned, it was working once upon a time, so it's extremely puzzling where the problem could be arising.

phildunlap

Is it possible that you're not using the latest NoSQL module? I guess if you had an older version and a lock had gotten stuck on that point in the database that would cause something like what you're seeing. You shouldn't be able to set any values to that target point via any means in that condition, though: none would make it into the database. If it were the NoSQL module, though, I would still expect a modbus device, say, to send the set command out.

AldoRamos

No, this is not using NoSQL.

And again, the target point is a Virtual Point (user input)

phildunlap

And you don't have obvious messages about Timer Cancelled, or running out of memory, or anything like that?

And you've tried restarting the instance?

I am certain the example I posted works, and I was using the version you're using.

AldoRamos

Correct, no “Timer Cancelled” messages, no running out of memory (since I added swap) or any other messages at this point.

I do occasionally get this error message:

WARN  2017-10-20 14:11:12,771 (com.serotonin.m2m2.rt.dataSource.PollingDataSource.incrementUnsuccessfulPolls:107) - Data Source GCI Input aborted 28 polls since it started.

And yes, I have restarted the instance. Several times. ;-)

phildunlap

Hmm, that's a real puzzler!

I have no context for what that data source is, so its having aborted polls is probably irrelevant. You say the source point is updating.

If the point link ran, and an error occurred in the SetPointWorkItem, it would have been logged. You could check your SQL logs if you haven't.

Is your instance bogged down, and perhaps every time you expect the point link to fire you see the number of medium priority work items increase, and that isn't decreasing, perhaps they are not executing.

You can launch your instance with ./ma.sh start and if anything were escaping to stderr you would see it.

You can launch Mango on a fresh database and try to replicate.

You can post or email JSON you think would replicate it and I'll try.

AldoRamos

We're preparing to upgrade that server to 3.2, so I'm putting off any further attempts until then. At that point, I'll try your suggestions (if the problem persists), and report back to you.

For what it's worth, we attempted creating an event handler to accomplish the same effect, but the result was the same.

We are able to change the value manually (user input) but having difficulty with any programmatic changes.

We'll update you on Monday. Have a great weekend.

Aldo

AldoRamos

Just noticed this interesting message in the logs, when shutting down:

INFO  2017-10-25 13:50:32,882 (com.serotonin.m2m2.rt.maint.BackgroundProcessing.joinTermination:363) - BackgroundProcessing waiting 5 more seconds for 3 active and 1300637 queued medium priority tasks to complete.
INFO  2017-10-25 13:50:36,927 (com.serotonin.m2m2.rt.maint.BackgroundProcessing.joinTermination:375) - 1300637 medium priority tasks forcefully terminated.

That does not sound normal, and it would explain the error we were already seeing:

FATAL 2017-10-24 13:40:41,368 (com.serotonin.m2m2.util.timeout.RejectedHighPriorityTaskEventGenerator.rejected:47) - High priority task: com.serotonin.m2m2.rt.dataImage.DataPointRT rejected because Task Currently Running

Thoughts? What would cause this?

P.S. I imported a backup of the settings from a few weeks ago, when it was working; no change

phildunlap

@phildunlap said in Are there Point Link (pointLink) tutorials, or examples?:

Is your instance bogged down, and perhaps every time you expect the point link to fire you see the number of medium priority work items increase, and that isn't decreasing, perhaps they are not executing.

AldoRamos

There really shouldn't be any significant load; it's just receiving on a Persistent TCP Data Source, waiting for user input on a Virtual Data Source, and the previously mentioned point links.

phildunlap

How big are your events and pointValues tables?

The NoSQL module is much, much more efficient than using the SQL table.