AkYtec GmbH has released a new TRM500 temperature controller for industrial ovens. This device is designed for temperature control in ovens, kilns, injection moulding machines (including hot runner systems), extruders, shrinks wrappers, PET blow moulding machines, homogenizers and other manufacturing equipment with electrical heaters.

The new temperature controller TRM500 is intended to control thermal processes (up to 2500 °C) and also to switch circuits with up to 30 A load capacity without any need for intermediate circuitry or relays.

The TRM500 is notable for its sufficient reliability, serviceability, optimum functionality and configuration simplicity.

This device has a very simple operation algorithm: input scan, producing an output signal, displaying the current temperature value. In addition, it is possible to organize high/low alarm due to two relay outputs. The TRM500 can be operated in two modes of control: on off control and PID control.

Process and digital inputs

The controller TRM500 has two inputs, namely, a process input and a digital input.

The process input is intended to connect temperature sensors. This input supports wide range of resistance thermometers (RTD) and thermocouples (TC). As a result, it is possible to choose the most suitable sensors by type and construction. The TRM500 supports 2-, 3- and 4-wire circuits of RTDs.

The digital one is used to switch the operation modes by means of an external push button or a switch:

  • Control on/off (for example, when loading/unloading the oven; see Fig. 1)
  • Manual/automatic control (see Fig. 2)
  • Setpoint switching (see Fig. 3)

The setpoint switching mode provides heat loss compensation caused by door opening. For example, there is two setpoints: process (200 °C) and compensation (380 °C). When the oven door is opened, the setpoint is automatically switched to 380 °C. In this case, the oven reheating is excluded and the general oven capacity is increased.

Output types

For implementing different control and alarm tasks the device is equipped with three outputs: two electromagnetic relays (OUT1 and OUT2) and one solid state relay (OUT3).

The TRM500 is delivered in two variants: TRM500-30A and TRM500-5A. The TRM500-30A has a built-in relay for maximal switching current of 30 A. This controller is designed for control of industrial and laboratory ovens with nominal capacity up to 6 kW without any auxiliary starters (in on off control mode). The relay of the TRM500-5A can switch circuits with switching current up to 5 A.

OUT2 (5 A relay) of both variants is used for alarm. Two relay outputs allow realizing of both low (relay 1) and high (relay 2) alarms. When the process temperature is out of limits, it can cause damaging of the oven content or reducing the oven lifetime. All this can be avoided due to a timely alarm.

For switching currents higher than 30 A or to make a temperature control in PID mode both variants of the device have the output OUT3 (0/5 V) on board. This output allows connecting a single-phase solid state relay (SSD) for up to 800 A or a three-phase SSR up to 120 A for switching current circuits in very powerful ovens. The connection diagram is shown in the Fig. 4.


The temperature controller TRM 500 is very easy in setup and operation. For example, the setpoint switching is carried out directly in the operation mode. To save time of the primary configuring, the device menu is divided in two parts: quick setup and full setup. The quick setup branch contents the most commonly used options: sensor type, mode of control, hysteresis and alarm limits. The rest functionality is available in the full setup.

Indicators and LEDs

The temperature controller has enhanced indication capacities. TRM500 is delivered with one (TRM500-5A) or two (TRM500-30A) indicators. Current process temperature is displayed on the first indicator. This one is a 7-segment 4-digit indicator of 20 mm digit height. Such height of the indicator provides a very good usability when working far away from the control cabinet. The second optional indicator is intended to display the setpoint. In manual mode the second indicator displays percentage of output capacity when the device is performing PID control. The output capacity value can be changed using the UP and DOWN buttons. Before switching back to automatic mode the TRM500 can memorize the last measured temperature value and use it later as a setpoint.

9 LEDs on the front panel help to recognize the output statuses and operation modes at a single glance. For example, the LEDs “TUP”, “TNORM” and “TDOWN” show whether the process temperature is included in the allowed range, or not (see Fig. 5).

Fig. 1 Fig. 2
control_on-off auto-man_control
Fig. 3 Fig. 4
setpoint_switching wiring
Fig. 5