PLC Program for Thermocouple

Thermocouple is a temperature sensing device that is widely used in industries. Its working principle is Seebeck effect and it generates millivolts in response to change in temperature. It is wired to a temperature controller that converts the millivolts to 4 to 20 mA DC that is supported by the analog input channel of any PLC i.e the Programmable logic controller. The 4 to 20 mA value is sample by the AI channel of the PLC program in Hexadecimal format. That Hex value need to be converted to meaningful value so that we can further manipulate for our own requirement. For this purpose, PLC program / Logic must be made for the analog sensor i.e Thermocouple in this case. All PLCs have the same procedure while i will be using Siemens S7-300 PLC in my Step 7 project. In PLC program, the built in functioin SCALE FC 105 would be utilized for scaling of the Thermocouple sensor. #plcprogramming #thermocouple #s7