'Multi-channel thermometer' seems fine, but I suspect that 'control' is the wrong word. 'Control' is a notorious 'false friend' when people are translating into English, and 'check' is usually the word that people need in this case. A thermometer does not control anything - it monitors or measures temperature. Perhaps something like 'multichannel temperature monitor for generators' might cover it?

I suggest : Multi-channel thermometer for generator status control This would be a thermometer with many channels which controls the status of generators I am not an engineer so I don't know if there is a better expression in English.