I'm using LV 2015, 32bit on two W7 laptops, and a cRIO 9036 chassis. I have the same program, configured differently, on all three targets. One laptop has been talking Modbus TCP to an industrial PLC-type controller for years, using a module I wrote specifically for that PLC instance. I recently put that module down on the cRIO. It now talks Modbus TCP to the same PLC at the same time, no problem, no errors.
Then I tried to put that same module on the 3rd target, the second W7 laptop. It returns data, which appears to be correct. But every read of a Modbus channel also returns this error:
Error 1 occurred at : Modbus 7.vi in MICAS Acquisition.vi Possible reasons: LabVIEW: An input parameter is invalid. For example if the input is a path, the path might contain a character not allowed by the OS such as ? or @.: SubVI in SubVIs.lvlib:TCP Master.lvclass:Protocol Write.vi:6190001->SubVIs.lvlib:IP Data Unit.lvclass:Write ADU Packet.vi:1820001->Modbus Master.lvclass:Read Input Registers.vi:5450001->Modbus 7.vi->MICAS Acquisition.vi
The firewall on the 3rd platform (2nd laptop) is turned off. All three platforms are plugged into the same Ethernet switch.
Any ideas what Error 1 means in this case? I did think that maybe three connections was "marginal" for the controller, so I did try stopping the first laptop and the cRIO and running JUST the 2nd laptop, but it still gets an error!
I found a few different instances where that error comes up. They are slightly different scenarios, but the error seems to be the same.
LabVIEW Error 1 or 6: Input Parameter is Invalid: https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z000000P6rgSAC
Error 1 Occurred at Open VI Reference:https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z0000019KbxSAE
Let me know if this helps or you have tried these steps already!