Reference Designators

[Tunalover]

Folks-
It used to be that IEEE 200/ANSI Y32.16 was the governing standard on electrical and electronic reference designators (e.g. 'R' nos for resistors, 'C' nos for capacitors, 'L' nos for inductors, E nos for terminals and antennae, etc.). ASME Y14.100-2000 invokes IEEE 200 and IEEE 315. Last week though I got a quote to buy these and learned that IEEE 200 has been cancelled with no replacement. Does that mean that only IEEE 315 is now in place?

I think it is an acceptable practice (and sometimes a preferred practice) to call out reference designations in lieu of find nos on an assembly drawing. Our company has a configuration manager who has never seen them anywhere but on circuit board drawings so she doubts they can be used elsewhere!

Granted this is done all the time on PWA/CCA drawings but is there some exclusion that limits their use only to there?

I've found it can make for a very clean drawing when you call components out by their reference designators! Of course the reference designators are included on the bill of material to show what their part nos are.

I'm caught in a company with no drafting experience on production DoD programs and with a CM group staffed (and managed) by people with no experience with "Level 3" documentation! I "lead them to water" regularly but can't get them to drink!




Tunalover

 

[wes616]

Tuna,

We have an internal standard dealing with this. I can't seem to think off the top of my head what outside source it references though. But basically we will "purchase" all electrical components on electrical prints. There each component is given a unique ref designator no. Then on mechanical instl's of the components, the ref designator is used to define the part.

In the PL, we list the Ref Des as REF and define weight for the component, so our stress guys don't have to look it up, but that's basically it.

sorry it's late.

Wes C.
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[CheckerRon]

As a drawing traditionalist using ref des's like find numbers sounds wierd to me, but then find numbers are optional (ASME Y14.34-1996, ¶ 5.6.2). What about components that don't carry ref des's however? Boxes, boards etc.? Specify them by part number only. If find numbers are optional, then not using them doesn't violate thre former Level 3 (now MIL-DTL-31000C ¶ 3.6.2.3).

 

[Tunalover]

CheckerRon-
You don't have to use ref designators exclusively. They are used in addition to find nos. Find nos are used for "non-electrical" parts. In the same drawing it is perfectly fine to call out electrical parts using reference designators.

Think about a PWA drawing: there are often "non-electrical" parts e.g. screws, connector accessories, and so forth and those are called out using find nos. On the same dwg ref designators are used to call out all the electrical parts.

When it comes to drafting I tend to avoid peoples' opinions because everybody has one and they're rarely based on cold hard facts (e.g. specs and stds). People tend to learn a certain way of doing things then carry it forward forevermore as THE way to do it. You for example see this practice as "weird" but if you dig into the specs you'll find that the above described method is one acceptable way of calling out parts on an assy dwg. Your outlook is shaped more by experience than on fact.


Tunalover