User Guide

Matrikon OPC Server for Allen Bradley
Page 33 of 49
Appendix A - ITEM ID SYNTAX
6.1 ADD ITEMS
The last step before reading and writing data is to add items to your group. This is done by
providing an Access Path and Item ID pair. The server uses this information to find the data you
are interested in.
If your client supports server browsing, you may not need to provide an Item ID, since you can
point and click to specify an Access Path and Item ID from the server browser.
The ProcessX server for Allen-Bradley PLCs does not use Access Paths. If your client asks you
to provide an Access Path, supply a blank.
Use the following format for the ItemID:
PLCNAME@[AB STYLE ADDRESS]
ItemID Description
PLCNAME Enter the name you assigned to this PLC during configuration.
AB STYLE
ADDRESS
Enter the address you wish to access, using the standard A-B format.
Consult the appropriate Addressing Reference Manual for your PLC.
The following are examples of valid Item IDs:
Plc1@N8:1
Plc1@N8:1/12
MyPLC@S:2/4
PLC-X@T4:1.EN
PLC-X@ST:1
Refer to Appendix A for a list of supported PLC-5 structured data types.
6.2 READ AND WRITE DATA
Your client may now read and write data to and from Allen-Bradley PLC registers. Some clients
will perform this activity automatically for you. Others may require that you specifically enable
data retrieval. Consult your client documentation for more detail.