Examples for OPC client and subscriber development in Python are now on GitHub: github.com/OPCLabs/Examples-QuickOPC-Python .

Note: QuickOPC now supports Python in much better way, cleaner syntax, and public packages (pypi.org/project/opclabs-quickopc/) on Python Package Index . See What's new in QuickOPC 2023.2 for more information. And, over 270 examples are available in the User's Guide!

Hello,

this may be because by default, QuickOPC reads ask the server to provide the value with "maximum age" of 1 second. In order to obtain the "absolutely latest" value, a read "from device" needs to be specified. opclabs.doc-that.com/files/onlinedocs/QuickOpc/Latest/User%2...m%20OPC%20Classic%20Items.html

Unfortunately the COM API does not support method overloads and this has to be done in more complicated manner than in .NET.

In short, you need to use ReadMultipleItemValues instead of ReadItemValue (even if it is with just one value), and pass in an array of parameter objects, and iniside these parameters, the "read from device" can be specified.

Please have a look at the following example - switch to the VBScript tab which is closer to Python code:
opclabs.doc-that.com/files/onlinedocs/QuickOpc/Latest/User%2...ems%20from%20the%20device.html

You will use this example (rewritten to Python) with following differences:
- one element in an array (and not 3), if you ae just reading 1 item
- call ReadMultipleItemValues and not ReadMultipleItems
- the result(s) will be of type ValueResult and not VtqResult (see e.g. opclabs.doc-that.com/files/onlinedocs/QuickOpc/Latest/User%2...0multiple%20item%20values.html )

Best regards

Hello.
A demo would be truly helpful.

OPC UA is not based on COM and thus there won't be any 32/64 bit issues like this. And it is modern technology and a way forward. Sometimes it can be troublesome to do the security correctly (certificates), but if you are considering it, certainly there are no objections from our side.

Best regards

No, thank you. We would actually need to manipulate registry and possibly even install our development environment there. And a lengthy process indeed. Nothing that you or we want to happen on the actual computer used for anything else.

Regards

Hello,
what do you mean by "it still looks the same"? Are you referring to the bitness text in the About box, or to the "CoCreateInstanceEx: Class not registered", or both?

Re "Regarding the 32/64 bit thing! Will the win32com.client connect as 32 bit also if python is running 32bit?": Yes

Regards