Intelligent building system
EVD4 is an evolved PID controller complete with driver for stepper motors specially designed for the management of electronic expansion valves in refrigerant circuits. It features sophisticated control functions
and can be used in many operating configurations in refrigeration and air-conditioning systems, such as:
- PID control of superheat with protection and safety compensation functions;
- PID control on one measurement (pressure or temperature);
- positioner for electronic expansion valves controlled by 4 to 20 mA or 0 to 10 Volt signal.
The device is configured and the address set via serial interface and the user interface software is stored in non-volatile memory.
This electric current is measured by a current transformer: by varying the level of water using a fill solenoid valve and due to the evaporation process, the current, and consequently steam production, can be modulated. Due to evaporation, the level of water decreases and must therefore be topped up. As the steam produced does not carry mineral salts, the salt concentration in the water and therefore the conductivity increases, and has to be periodically diluted by draining part of it using the drain pump and replacing it with new water.
The CAREL DPW* series serial probes are devices used for applications in the air-conditioning, refrigeration, heating and air handling sectors. These are installed in combination with the controllers that feature the serial connection. As well as the wall-mounted room probes, industrial and duct versions are also available.