Input/Output coordinates for Open Platform Communications (OPC)

The Input/Output coordinates for the Open Platform Communications (OPC) protocol represent the existing group and item names in the OPC server.

The Input and Output tabs in the analog, status, and rate records each contain a Coordinates field. These coordinates are used by the OPC protocol, and represent the existing group and item names in the OPC Server. All coordinates reference the OPC Group definitions set in the opc Row Edit dialog box. Their format is: groupnumber:itemname.

groupnumber:itemname is a zero-terminated string with a total length of 128 characters (127+null).

Groups are collections of data points that share and adhere to a specified update rate. Group definitions range from 1 to 20; the group number corresponds to the Row number of the OPC Group Definition tab.

itemname is a zero-terminated string that represents point coordinates in the OPC server.

The image below shows an example of an analog configuration. You can see how the Output Coordinates field uses the format above. The Output coordinates, which are entered as 2:Random.Int1, reference the group definition in the second row of the opc Row Edit dialog box. The coordinates represent the location in the remote to which this analog point corresponds. Input and output coordinates need to be set for all analog, status, multistate, and rate records using the same format.