Create a circuit to act as the secondary controller which will interface with a home automation system

[R.Alamsha]

May be you need some protocol gateway. Check this answer.

Connecting Ignition to an iNOEX production line?

I have come across these kind of systems. One such system was running on a “top secret” soft PLC written in c language. My guess is mostly it will be a Modbus PLC. Find the communication cable, connect it to your laptop, and use some data capturing tools or protocol sniffer which is freely available on internet. Copy paste the data packets and do some google research. You will get some clue. I did this technique to develop a communication driver for a top secret control panel and found it was Mo…