Communicating with a HMI programmatically

[duannguyen]

Hello everyone.

I was wondering if I could get some help with a project that been push onto to me this past week. My background is in computer science and I'm more at home getting a pointer to video memory and drawing my interfaces that way then going through all these hoops.

We have a HMI device (MT8070iE) which meets our explosive testing requirement. I have the HMI device connected to a switch. A PC is also connected to this switch as well.

I was wondering if there is any way to talk to the HMI programmatically via TCP/IP using the computer or small SOC (system on a chip)?

For example, opening a port and changing the value of the bar chart. Please point me to a tutorial online (if any) that can get me started.

So far, I have done this using the EasyBuilder Pro that came with the HMI.

And I was unable to deploy it just fine over Ethernet.

What I want to do is to be able to change the value of the vertical bar chart from the computer that is on the switch. I have added a MODBUS TCP/IP (PLC) to the project and pointed the IP address to the computer on the switch. But not quite sure if it should be a MODBUS Server instead? I have also changed the address of the bar chart to "RW" and 2000.

Currently, I'm stuck and the getting started PDFs and other online resources I have found are not helping me in this regard. I'm currently looking at the MODBUS protocol but it might be reinventing the wheel if I were to write it myself.

Thanks again.

 

[Saffa]

Generally, most people use HMIs as slave devices when using modbus TCP. The HMI polls for data (i.e. acts as a modbus master) from a slave, typically a PLC.

I'm assuming that your PC application is the data source. In this case you will need to implement a modbus master on the PC. There are plenty of open source libraries on SourceForge etc that can be used to accomplish this. If you're writing the PC application then this can be integrated relatively easily.

If your HMI supports a modbus slave option, then you can write from the PC to the HMI instead if you prefer. Again plenty of modbus slave implementations online.