... Relay, SSR or 4-20mA output controller Digital Temperature Controller Toky AI508 (48mm*96mm) series temperature controller with following features: a. TC/RTD ... arithmetic, d. PID auto-tuning for different system(quick heating/cooling or slow heating system), e. option control output, modularization design, ... one alarm or two alarm can be choosed, applicable to system tempreature control environment.