Hi,

I have a small HVAC application with temperature and fan speed controlled by a PLC (Siemens PLC). There are start/stop buttons and a variable pot for the temperature set point locally, but I would also like to be able to view and control the system on Labview.
The PLC has a serial port and will support Modbus but I have no experience with Modbus or setting of it.
I am using Labview 8.2 with the DSC Module, so I think I have all I need to set it up. (if you help)
I tried to set up one of the inputs as a shared variable but it didn't work, not sure if it is the right way.
I also tried some of the VI's from User Libraries > NI Modbus, but because I have no luck with these I got lost.
If someone can explain to me how to set this up or if you have a VI that I can easily modify I will be very thankful.