Introduction of PPC/EP regulator

Based on the advanced IdealTM technology, Cosy's PXK-series' proportional pressure valves can effectively boost the performance of varied applications with outstanding precision and fast response. This control technology changes our lives every day and we are committed to improving and simplifying people’s life by concentration on continuous initiative of control technology.

Basic Principle

The above diagram shows a typical closed loop control circuit. The PLC or PAC control system connects PPC devices with the human machine interface computer. The reference variable W (set value usually is 4-20mA or 0-10V) is usually transmitted from the AO module of the PLC system to the PPC. The integrated high precision pressure sensor measures the actual output pressure X and sends it to the PLC as a feedback signal. The reference point detects this deviation and processes the differences to the PLC controllers, finally generates update W to PPC. The PPC regulates the pressure to actuator in order to control the final control elements. This process runs continuously, so that changes in the reference variable are always detected until the whole system achieves the set value.

Comparison to the open loop technology

Closed loop technology can provide much higher accuracy, more stability and less setting time.

The overall system is under the dynamic control, which means that either W and X are both variable. Changing indication becomes stable till the final set value is achieved.However, a system deviation will happen also, when flow through the valve changes in response to a switching action, a cylinder movement or a change in load. The disturbance variable from actuator elements will also cause a system deviation. Here is the example, if the pressure drops in the air supply. In addition to these disturbances, there are also differences resulting from temperature drift or time shift. In all these cases, Cosys PPC can maintain the stability even if these challenges. Thanks to the excellence of embedded IC integrated inside, Cosys PPC can detect the deviation so fast that regulate the pressure in very time. PPC’s robust performance could benefit from it as well.