There are many vendors and sources of PLCs: Automation Direct, FactoryMation, B&B Electronics, and yes, even eBay, among others. I will use the Click PLC available from Automation Direct as an example ...
As engineers, we often need to design a customized control system or interface to address a need which can”t be met with an off-the-shelf interface device. In the used-to-be days, we”d get a Bud box, ...