Ignition 8.3 Siemens Enhanced Driver OPC Item Path Syntax

Ignition
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1

Hi all, I am using Ignition 8.3 with the Siemens Enhanced driver with S7 symbolic communication to an S7-1500 and came across some unexpected behavior with the OPC item paths that I wanted to clarify.

I am copying over some old UDTs + tags from an 8.1 project where the same S7-1500 PLC was hosting an OPC-UA server for testing. When I add a new tag from the Ignition OPC-UA server directly from the tag browser, the tag path does not contain any quotation marks and seems to work totally fine.

The weird part to me was that I have some tags that still have quotation marks in the OPC item path from OPC syntax but they still work.

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The Siemens Enhanced Driver documentation does not indicate anything about quotes, so I’m curious when/if they can/should be used.

Thank you!

2

I don't think we document the item path for symbolic addressing at all. That being said, quotes are required for individual parts of the path that contain special characters.

For example, these addresses all point to different tags:

  • "Block.One"."Tag.One"
  • "Block.One.Tag".One
  • "Block.One".Tag.One

Then, I think these addresses are also valid but point to one of the above tags:

  • "Block.One.Tag"."One"
  • "Block.One".Tag."One"
  • "Block.One"."Tag"."One"

Most, if not all, tag names that have non-alphanumeric characters will have quotes around them when browsing. Some characters may be fine without quotes :person_shrugging:

3

I see, thank you for the reply! That makes total sense.