Temperature is one of the most important parameter in the industrial control. Any physical change and chemical reaction are closely related with the temperature. Temperature control mode is diverse, and PLC is high reliability, easy to learn and use, use of PLC is one of the comparative advantages of the control.
This article describes what based on Siemens plc (PLC) S7-200 's temperature control system design. The hardware used a CPU model for 226 of S7-200, K-type thermocouple, TD200 HMI and acquisition module EM231. Thermocouple as the temperature acquisition components, acquisition of signal EM231 processing can put data into the PLC for processing, and finally into the man-machine interface displays the current temperature values.