PID Temperature Controller with Four Digit Display has easy to use PID temperature controller, 4 digit single row display, selectable sensor input from keyboard. The Controller has the feature of programmable lower and upper set point limits, programmable control action on off/ PID control programmable hysteresis in on off mode. The Controller has programmable time delay to activate output in on off mode, selectable heat/ cool logic in on-off control mode, user selectable, and relay or SSR drive output, program lock function to prevent unauthorized tampering. The PID Temperature Controller with Four Digit Display has operating temperature ranging from 0 to 50 ° C.