How many copies of SDK must I purchase?

If I want to create a custom data monitor application using the C API and run it on my machine, plus ten other machines on my plant floor, how many copies and what versions of RSLinx Classic do I need to purchase?

One copy of RSLinx Classic SDK and ten copies of either RSLinx Classic Professional or RSLinx Classic OEM must be purchased. The RSLinx Classic SDK version (which comes with one copy of RSLinx Classic OEM) allows you to develop, test, and run the application on your machine. The ten copies of either RSLinx Classic Professional or RSLinx Classic OEM are for each of the machines on the plant floor that will run the custom application.