O/T Item designations on drawings

This is really a European question but all are free to chip in.

It has come to my attention that the item designations used for many years in electrical drawings have been superseded. I'm talking about -105K1 as an example being the 1st relay on page 105 of a set of drawings.

The designation "K" comes from the standard AS3702-1989 where "K" is designated: "Relays, contactors"

AS3702 has been replaced by IEC 81346 and table 1 of part 2 now describes "K" as "object for treating input signals and providing an
appropriate output"

My question is: Does anyone actually use IEC 81346 for item designations or is everyone still using AS3702?

Nick

Nick,

I have a lot of machines here from KHS and Krones, and they all still use AS3702.

Some of this stuff is only a year old.

Cheers

Mark

The newer definition appears to be a more generalised statement about what a relay/contactor does.

Manglemender said:

"object for treating input signals and providing an appropriate output"

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If you think about it an 'old' K relay did that. The input would be from the PLC output normally and its output would be power to turn on a motor, heater, valve, etc. Also, interposing relays take an input (sensor) and give an output (PLC input or tie into a 'power' K coil wire as a safety, or other use.

Some new engineer just had to make it read 'his way'

Originally posted by I_Automation::

If you think about it an 'old' K relay did that.

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True enough. But so did the plc the relay was connected to, the motion controller in the enclosure with the plc, the drive the motion controller or plc was connected to and, yes, any sensor located on the machine. The new definition is unnecessarily broad.

I think your second point is probably the case. Someone was sitting around with nothing to do and decided the designators needed a "fresh look".

Keith

Reading the standard a bit more, every device now gets a 2 letter prefix so:

KF = information processing object for relaying electric signals. Example: electric signal relaying object coupler, electric network bridge, electrical network switch,
repeater, relay, time relay.

There are literally hundreds of these definitions in the IEC 81346. I'm normally a bit fan of Europe but this really is Eurobable and I'm prepared to bet that if I were to produce a machine using these "standardised" abreviations then no-one would have a clue what they were based on the designation.

Nick

Without all these new standards how could these bodies justify their wages

parky said:

Without all these new standards how could these bodies justify their wages

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Years back I worked for a distributor for lawn & garden equipment & went to the factory in Wisconsin a few times.

They had on staff almost 50 engineers and realistically could have cut that down to 2 or 3.

The rest dug up old drawings from machines built in the 60's and kept coming up with updated parts and retrofit kits to use the new parts, and what they were producing was so over-engineered because these 47 people had to do something to earn their pay.

Remember the joke about the bowling ball salesman that never took a vacation or sick day - if he ever wasn't there one day they would figure out the bowling balls sold themselves and he didn't do anything.