Access V280

[darknesspic]

1.I have a little confuse why we need to use OPC server because even we can access the memories of PLC by read/write command(ASCII format) serial communication with PC?

2.What cases we have to use OPC server?

Thank you.

[Eyal Koren]

Hi darknesspic,

OPC is a software interface standard that allows Windows based programs to communicate with industrial hardware devices.

The OPC server is a software program that converts the hardware communication protocol used by a PLC into the OPC protocol. The OPC client software is any program that needs to connect to the hardware, such as an HMI. The OPC client uses the OPC server to get data from or send commands to the hardware.

The value of OPC is that it is an open standard, which means lower costs for manufacturers and more options for users. Hardware manufacturers need only provide a single OPC server for their devices to communicate with any OPC client. Software vendors simply include OPC client capabilities in their products and they become instantly compatible with thousands of hardware devices. Users can choose any OPC client software they need, resting assured that it will communicate seamlessly with their OPC-enabled hardware, and vice-versa.

One commonly used application for OPC server is HMI system in a plant's control room. The operator can control several systems by different vendors from a single interface.