Hi , I started my plc about 5 years ago for plastic unit but now When I turn them on, the correct screens appear on the HMI terminal, but no data is coming through from the PLC. After a few seconds, a pop-up appears sayingPLC No Response 00-00-0". Does anyone know the meaning of this message.Then I am on and off several times so that the device is turned on and working properly. I DON'T KNOW ?