Why and/or whom came up with safety terminal designations?

[Watsonator]

So I have always been bugged my safety. In as much as when it does not work it is a pain to troubleshoot. For example, power in is A1 & out is A2. I'm thinking that this is because in whichever country it was established Power or Potential starts with the letter 'A'? BUT, Everyone is following the same clandestine plan, seems to be a "New World P.I.T.A." to me. SICK, A-B, ABB, all have safety controllers and all use the same labels.

Moving on to the meat of my inquiry; Why is the other terminals labeled as such and not just simple IN (S11,S21, 13, 14, 23,24), OUT (S34, Y32, L12,L11), and relays (K1, K2) ectara, ectara, ectara.... Named logically? Or I suppose in a manner a normal person could understand. I mean really its like having a conversation in all code. "My X1, has really been Y32, never S11."

If anyone has a document on this please do share. I would like to have the codex and be able to understand instead of memorizing these obtuse designations.

 

[Watsonator]

Whos with me that...

A1 should 24 VDC
A2 = 0 VDC
K1 = SR1 (Safety Relay1)
Y32 = AUX
S43 = Reset

Red = Bad, closed & Green = Good, open.

Safety should be simple, not requiring a codex...IMHO

Thanks in advance!

 

[padees]

No wonder you are having issues.
These obtuse designations are really only understood by someone from India that is very fluent in playing a one stringed instrument.


Actually, most safety components do follow this type of numbering form.


YMMV...


What is more important is you apply what you have properly.

 

[Tharon]

They might not be readily understandable to the layman, but they are fairly common across manufacturers.

And of course the important part is that they match the manual, and you have the manual available.

While it might be nice to name them something more meaningful, the meaning does tend to change depending on how you configure the safety relay. That reset input might not always be considered a reset input, if it is setup for automatic reset, and being used to monitor EDM instead.

Edit:
Even "A1" might not always be "24VDC"

 

[busarider29]

they might not be readily understandable to the layman, but they are fairly common across manufacturers.

And of course the important part is that they match the manual, and you have the manual available.

While it might be nice to name them something more meaningful, the meaning does tend to change depending on how you configure the safety relay. That reset input might not always be considered a reset input, if it is setup for automatic reset, and being used to monitor edm instead.

Edit:
Even "a1" might not always be "24vdc"

+1