There is not that much to doing security systems... Just firing an output for 3 to 5 seconds.... Intercom systems are not that hard either. Again, just maintaining a bit to establish an audio path - the intercom system does the rest. What gets a little tricky, is door alarms. If the door opens, and the PLC doesn't power the lock. But, I have seen some prisons with some crazy stuff! I did one a few years back that was crazy! 13 different buildings, all with their own PLC, networked over Fiber optic ethernet, with 34 touch screens running RS View. Started out using Ingear OPC, but found out that Ingear works great, when you ask it to talk to a single PLC, just don't ask it to talk to multiple at the same time! Ended up switching to Kepware at the last minute! I swear by Kepware from here on out!
