PriSim

Hello Dear, First of all great and nice forum. I am newbie in PLC field and a student of engineering. I want to work on PLC with GSM module, but the problem is how to chose the PLC (company and model) that supports AT-commands like simple micro controller does.I know about ladder logic and modbus protocols a little bit. PLC must be economical too so that i can buy it. Please guide me regarding this issue. Regards!