Logic Control - Controller / logic / Counter / Timer / Remote control / Everything: Siemens Logo - We use this a lot for timers, controlling, counting, all sorts of things. It does a lot even if you don’t see it, such as controlling the hoists and winches or switching things on after a pre-determined time or interfaced to a laptop. Our version has 6 logic inputs for switches, external sensors, remote control interface etc and 4 relay outputs (We would like more outputs but we can live with the 4. Thank you to the person who donated it. Note the picture is a publicity picture not ours. As we depend on it so much we could have had so many pictures and links but in the end we just picked the one below as it's recent and uses it a few times.