Device Labeling Poll Results

several people sharing their opinions and voicing concerns and c

A couple of weeks ago I started a poll on device numbering methods, here are the results. Responses came from comments on this site and five different Linked In forums.

Method 1: Labeling the device based on the I/O point it is connected to: 5 votes

Method 2: Labeling the device based on where it appears in the electrical schematics (i.e. line/page number): 12 votes

Method 3: Labeling the device based on mechanical or physical layout (i.e. P&ID or similar): 7 votes

Responses were broken down much as I thought they would be. Method one voters were mostly OEMs and method three voters seemed to come from a process control background or from Europe (IEC standards). Method two seems to be the default for manufacturing plants and machine builders, at least in this country.

Though only 24 people actually had an opinion, several more commented on the subject without expressing a preference. Quite a few more hit “like” on the topic without making a comment.

As I mentioned, I have had to use all three on different projects depending on customer standards and preferences.

Thanks for all of the comments and responses!


Electrical Engineer and business owner from the Nashville, Tennessee area. I also play music, Chess and Go.

1 Comment on “Device Labeling Poll Results

  1. As a systems integrator, I would definitely choose option #2 that utilizes the page and line number approach for the following reasons:
    1. This tagging approach is not dependent on the PLC platform which can often requiring different nomenclature. Plus with the advent of PLC platforms with user defined numbering schemes, there may not be a defined naming convention. I have also worked on many “upgrade” projects where an old PLC is being replaced/upgraded and who wants to renumber all the wires and devices because the PLC platform has changed? Nobody, that’s who.
    2. Typically, option #2 is utilized for all other schematics anyway (for factory automation projects) so keeping this approach for the I/O only seems to make sense for consistency.
    3. Most importantly, the page and line number numbering approach is the most efficient method for directing the maintenance technician to the appropriate location in the drawings when a problem occurs that needs to be addressed.