Digital Temperature Controller

EK491 is a Digital Temperature Indicator and Controller. It is single input accepts J-type (Iron/Constantan) and K-type (Chromel/Alumel) thermocouples, Pt100 RTD and linear (millivolt or milliamp) input. A large LED display on the front of the unit indicates either the process value or user-defined setpoint, which is easily programmed via a 10-turn trimpot. EK491’s single electromagnetic relay triggers heating, cooling, or high and low alarms for its single setpoint. This is a highly accurate controller, with an error as low as 0.1% for linear inputs and no more than 1% for thermocouples. EK491 is conventionally an ON-OFF controller that outputs a discrete signal, but can also be used in Time-Proportioning Mode which turns the actuator on and off for periods proportional to the desired control effort, to emulate a continuous actuator that can generate a control effort between 0 and 100%. It also retransmits an isolated output signal to other devices such as a Programmable Logic Controller (PLC) or Solid-State Relay (SSR). Signal isolation protects your devices and machines downstream of our instruments from damaging fluctuations in the input signal. By including input terminals in the excitation loop, EK491 provides power for two-wire 4-20 transmitters. The controller’s modular design contains zero-wiring making it virtually shockproof.