I want to do a small size SCADA to communicate with PLC tought COM port by using VB. How to write the program in order to get the data from PLC by some scanning interval time.
But it's simple and if you dont need very high speed and/or precision the job can be done with minimal mess and low cost also. By the way what tools You suggest for jobs like this?
You need a DDE/OLE server to provide data to application. These range from $99 to $300. I like DSDDE from automationdirect. Using VB, it's fairly straightforward to connect to server and communicate your information. VB has many data-aware controls that will draw info from server readily. Writing to the server is fairly easy as well. Get the DSDDE from