# Ignition 8.1 - Allen bradley - How to write OPC Item Path **URL:** \ **Category:** Ignition\ **Tags:** ignition81\ **Created:** [June 17, 2026, 1:32pm UTC](https://forum.inductiveautomation.com/t/ignition-8-1-allen-bradley-how-to-write-opc-item-path/116032 "2026-06-17T13:32:09Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Jesus\_Mariano\_Moreno](https://avatars.discourse-cdn.com/v4/letter/j/57b2e6/32.png) [@Jesus\_Mariano\_Moreno](https://forum.inductiveautomation.com/u/Jesus_Mariano_Moreno)\ **Post date:** [June 17, 2026, 1:32pm UTC](https://forum.inductiveautomation.com/t/ignition-8-1-allen-bradley-how-to-write-opc-item-path/116032/1 "2026-06-17T13:32:09Z")
I need to communicate an Ignition 8.1.47 with an Allen Bradley PLC through a device (PLC3) of type Allen-Bradley Logix Driver. The thing is, I'm not clear on how to fill in the OPC ItemPath field in order to communicate with the memory addresses. For example, the boolean B9:15/6. I tried with ns=1;s=[PLC3]B9:15/6 but it gives me a Configuration Error. How should I fill in the OPC Item path to reach the signal? ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [June 17, 2026, 1:38pm UTC](https://forum.inductiveautomation.com/t/ignition-8-1-allen-bradley-how-to-write-opc-item-path/116032/2 "2026-06-17T13:38:13Z")
The AB Logix driver is for ControlLogix and CompactLogix devices only, and only for relatively modern firmware. There is no IA driver for the ancient PLC3 family. The PLC5 driver **might** work. Please share the precise model and version of your PLC. ---
**Author:** ![Jesus\_Mariano\_Moreno](https://avatars.discourse-cdn.com/v4/letter/j/57b2e6/32.png) [@Jesus\_Mariano\_Moreno](https://forum.inductiveautomation.com/u/Jesus_Mariano_Moreno)\ **Post date:** [June 18, 2026, 7:56am UTC](https://forum.inductiveautomation.com/t/ignition-8-1-allen-bradley-how-to-write-opc-item-path/116032/3 "2026-06-18T07:56:37Z")
This is the PLC model: 5069-L320ER CompactLogix, 5380 Controler ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/6/c/6c3f8ab4f28f4387acd15ef7bbcbc37a0991fbb3.jpeg) I have an Allen-Bradley Logix Driver called PLC3 in Ignition, and its connection status is "Connected",. ---
**Author:** ![lane.duncan](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/lane.duncan/32/83700_2.png) [@lane.duncan](https://forum.inductiveautomation.com/u/lane.duncan)\ **Post date:** [June 18, 2026, 10:21am UTC](https://forum.inductiveautomation.com/t/ignition-8-1-allen-bradley-how-to-write-opc-item-path/116032/4 "2026-06-18T10:21:16Z")
This is a fairly new CompactLogix, which uses tag names like “motor\_start” and “motor\_running” An address like B9:15/6 is used for legacy PLC5 and SLC500 controllers, not CompactLogix. Can you browse the PLC tags with the Ignition tag browser? > **[Tag Browser | Ignition User Manual](https://www.docs.inductiveautomation.com/docs/8.3/platform/tags/tag-browser)** > > The Tag Browser is the central location for interaction with all types of tags on your system. It gives you full view of the tags including the current value, datatype, and any traits. When panels are in their default configuration in the Designer,... ---
**Author:** ![smcfarlane](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/smcfarlane/32/42150_2.png) [@smcfarlane](https://forum.inductiveautomation.com/u/smcfarlane)\ **Post date:** [June 18, 2026, 1:31pm UTC](https://forum.inductiveautomation.com/t/ignition-8-1-allen-bradley-how-to-write-opc-item-path/116032/5 "2026-06-18T13:31:24Z")
Use the tag browser. You can do this multiple ways. ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/c/d/cd626d0281b7ae3e96394ec917bec647197acfa6.png) Then from that window you can expand your PLCs to get down to the tags like so ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/0/8/084ebe0a92869132ab95235b7ce38c0e2d767604.png) Or from the tag creation window. Create an opc tag and browse devices by clicking the icon on the right side of the OPC Item Path box ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/f/9/f9af9d685dc55f0bd2b82fed9bad528a092040d9.png) ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [June 18, 2026, 1:36pm UTC](https://forum.inductiveautomation.com/t/ignition-8-1-allen-bradley-how-to-write-opc-item-path/116032/6 "2026-06-18T13:36:39Z")
Be aware that when a legacy AB PLC (PLC2,3,5, SLC500) is converted to modern Logix, the files' type & number become a Logix tag name, and the data is structured similarly, but the syntax within the modern conversion changes. `B9:15/6` will becomes `B9[15].6`, using square brackets for array subscripts, and a dot before a bit number. The forward slash is **not** valid as a bit delimiter in modern Logix. Nor can you use the colon for the array subscript. ---
**Author:** ![Jesus\_Mariano\_Moreno](https://avatars.discourse-cdn.com/v4/letter/j/57b2e6/32.png) [@Jesus\_Mariano\_Moreno](https://forum.inductiveautomation.com/u/Jesus_Mariano_Moreno)\ **Post date:** [June 19, 2026, 8:05am UTC](https://forum.inductiveautomation.com/t/ignition-8-1-allen-bradley-how-to-write-opc-item-path/116032/7 "2026-06-19T08:05:10Z")
That's exactly what I needed. Thank you so much!