Error writing to tag: array element type mismatch

Ignition
1

Hello everyone,

I've made a template in Perspective, that allows me to monitor and configure a Phoenix Contact Caparoc Circuit Breaker. This template is connected to an according UDT that has a relatively complex structure. The connection between the tags in the PLC and Ignition Gateway works just fine, i can monitor and display all the tags in the UDT and the data is correct. The perspective template also displays all the data correctly.

To configure some values I am using a numeric entry field with a indirect bidirectional tag binding. These values are defined as a Byte-Array withing the Caparoc UDT. When I change these values in the PLC they are correctly displayed in the entry field. But as soon as I want to change the value via Ignition, i get the following error exception:

Error writing to tag '[default]Caparoc/slots/0/setup/setChannelCurrent': array element type mismatch.

Here a tag path to the value I want to manipulate:
[default]Caparoc/slots/3/setup/setChannelCurrent[0]

Did anyone esle have a similar problem? Are there any ideas, what causes the error exception?

2

Maybe if you post some screenshots of the tags and the props of the numeric entry field it will be a bit clearer.
Also your error listed is using a different path to the tag path you listed, so that indicates you are missing something, as a binding uses the same path for both read and write.

3

When you wish to write array types, you must use actual java arrays (from the jarray jython module). For most OPC types, you cannot manipulate individual elements--you have to write the whole array every time.

4

Hi,

sorry for the very late reply, this month was fairly busy.

Thank you both for the recomendations! I am very new here and eiger to learn :slight_smile:

Sadly I dont have the posibillity to connect to the plant anymore but I can send some screenshots from the designer with the explanations (hopefully, this can provide some of the missing information) whine simulating the values.

Here is a screenshot of a Caparoc slot UDT instance with the variables Byte[4] array I am trying to access:

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So as you can see I do have the OPC connection to the variables and I also display the values correctly in Ignition.

Here is a page, where I try to change the current setpoint (Perspective Workstation):

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image825×594 10.2 KB

As you see the values are displayed here correctly aswell.

Here is a binding in Ignition designer:

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image786×593 37 KB

The tagPath param has following value (explicitly for this slot): [default]Caparoc/slots/0

So as I described before, as soon as I try to change the value of the current setpoint I get following error:
Error writing to setChannelCurrent[0]: Error_Exception
Error writing to tag '[default]Caparoc/slots/0/setup/setChannelCurrent': array element type mismatch

At the same time I am using similar methode to enable/disable each channel via a Bool[4] array. The binding in the designer looks identically.

And in this case I can enable/disable every single channel without any problems. So I can reach to every single element of an array. Something goes wrong while writing the values into the numeric entry field...