In each Vision PLC, I take a reading every minute, which is saved to a Data Table.
DataXport then connects with each PLC at a given schedule, copies the Data Table, and saves to an Excel file on a shared network drive. (some of the PLC's are read only once or twice a day, others are read every 15 minutes as the end user of the data wants close to real time updates).
The end user of the data, reads the Excel file on a similar schedule (but not at the same minute) and puts it into fancy charts and graphs for every one to see.....
run time error 3709 says;
"The connection cannot be used to perform this operation. It is either closed or invalid in this context."
I'm not sure if the connection in question is the connection from DataXport reading one of the PLC's, or from DataXport saving an Excel file to the network drive.
And of course, the error always seems to pop up when I'm out of the plant for a couple of days, and then I have to listen to the end users griping about missing information...
Which of course make me look like an incompetent boob having created such an unstable data collection process....
Until we will update RN/Help, you can use next to check if MODBUS limitation is working or not in your version:
As soon as you can write into stated SI/SB, MODBUS limitation should work.
*System registers are write protected, if not used for additional functions.
At this time only MIs and MBs MODBUS limitation works.
We added request to wish loist for feature implementation.
Does the problem reproduces if you download the project to a different PLC?
If so, send the project to Unitronics support with the instructions on which page and which image, so they can try to reproduce it here, and if it does then it will be forwarded to the R&D.
What version of UniLogic are you using?