modbus DSC

[LW42]

Good morning,

I want to make a NI cRIO9073 speak with a Maple HMI (Touch Screen) using an RS232 connection. Unfortunately, I have no previous experience, thus I have to confront lots of difficulties. In order to obtain this communication up to now I made some efforts which include: create a project, adding the cRIO ,then create an I/O modbus slave server and finally a shared variable. I have doubts about the properties setting of shared variable. What kind of variable type do I need, enable aliasing? What I was trying to do was writing to a DO channel of cRIO as a first test. I am attaching a screenshot of the project I made. Up to now I tried to apply instructions I found in the link: how to turn an RT target into a Modbus slave using I/O servers, however for serial (RS232) connection, but my HMI displays a message that can’t find the PLC. I checked settings like baud rate etc and everything seems ok.

Any possible help or instruction will be appreciated

Thank you in advance

[A_Patel]

Hi thorfano,

Can you read the variables on the cRIO?

Flash

[LW42]

Hello A_Patel,

Could you please be more specific? I have no interface to read or write since HMI displays a message that can not find the PLC. Of course I can read and write if I use as interface my PC (by creating the proper vis of course).

Best Regards

[A_Patel]

Hi thorfano,

I take it you do not have LabVIEW DSC. Is this correct?

In that case you will need to use the Modbus library. Found here:

https://forums.ni.com/t5/Reference-Design-Content/LabVIEW-Modbus-API/ta-p/3524019

Flash

[LW42]

Hello A_Patel,

I have downloaded the DSC module in a trial version. My intention was to check that my work can be done this way and then buy DSC. I am afraid I am too unexperienced to use the other way you propose (using the Modbus Library).

Best Regards

[A_Patel]

Hi thorfano,

Did you follow the instructions on the following to set up the variable:

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA03q000000YFeECAW&l=en-US

Also, have you been able to communicate with the PLC with anyother software?

Flash

[LW42]

Good Morning A_Patel,

Yes, I have already used the link proposed and already checked that the server works by using my PC as interface. In addition, I have already tested the functionality of cRIO (I have written and read to and from the same DO channel that I am trying to use in the touch panel application). I am afraid that it is difficult to solve the problem (if it is a problem and not luck of communication between the two devices, Touch panel and cRIO, due to software issues). Anyway, thank you for your consideration.

Best Regards