ISO 81346 Device identification Standard

Are you new to EPLAN?
Are you confused about what the standard device tags are for IEC and NFPA projects?
Are you finding yourself work on projects with more than one control panel and the question of device tagging standards has been discussed?
Are you confused as to what to do?

EPLAN fully embraces and enables the use of a fantastic principal for structuring objects and information in complex systems. In the EPLAN world we tend to focus on devices used in electrical systems but this system can be used to help identify and organize just about any group of objects. This system is broadly identified as the ISO standard 81346 and a good source of  information can be found at

Here is a link to a YouTube video featuring Henrik Balslev the founder of Systems Engineering A/S describing the RDS (reference designation system)

To simplify this article I will focus on the essential concepts that this standard introduces.

The creators of the ISO 81346 standard believe that the principals of this standard can be used to describe any complex system simply by identifying three criteria:

  1. Everything can be regarded as a system
  2. System elements are related by three types of relations
  3. It is necessary to label the system elements to enable identification

That’s really the essence of the standard, the associated sub standards more fully define the details of these relations but you should get the basic idea.

Here in the USA we have a somewhat similar standard that is used extensively in the process industry, its a mixture of several standards such as ISA 5.1, 5.4 and ISA 95. I would argue that the IEC system is much broader in scope and more universal but that’s my opinion.

So I previously mentioned the three types of relations, the standard goes on to describe these in more detail and since this websites focus is on electrical engineering I will also provide context for that, in essence there are:

A functional aspect (==) or (=)
What is the function the system or sub-system?
What is the function of this particular circuit?
This aspect describes a group of objects that serve a purpose of providing a function to the system
Often described with three letters but this could be anything including a circuit number.

A location aspect (++) or (+)
Where is the object located?
We are now describing location properties of the individual devices that are members of the functional group.
For most readers this will be an enclosure, a chassis, or a named field location

A product aspect (–) or (-)
Describe the technical properties of the product or device
These are typically reference designators used to classify components
For NFPA designers this might look like: CB, CON, CR, PS, F, CBL
For IEC designers this might look like: QA, QB, KF, TA, XD

When you put it all together you have a system that can provide a device tag that uniquely identifies every component within a system. The standard also allows for modifiers such as loop numbers or process area IDs. I have provided an example below of how a system like this might be implemented for a simple transport. This also enables a pathway to functional design methods in your electrical designs so that circuits can be quickly copied, both manually or automatically, to rapidly create new projects.


If you would like to learn more about how to implement this standard, please feel free to contact us here at Multiline Designs to discuss your next project.

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