Schematic Symbol questions

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Patio
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Schematic Symbol questions

Post by Patio »

Hi everyone,
I am helping Harold V, with the electrical part of getting a German cylindrical grinder he has, working. We have solved most of the operation problems.
This is a picture of the circuit I am tracing. This is some sort of proximity sensor, I believe. I have not been able to find the symbol in any of the normal charts. It may need replacing so I am trying to find out what type it is and its characteristics. Any ideas?
20180910_182218a1.jpg
Any help would be appreciated.
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tornitore45
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Re: Schematic Symbol questions

Post by tornitore45 »

Never seen one like that. We can only guess.
a) The small circle could be indicating a terminal, instead of using the dot.

b) The circled symbol wiggles side is the input side. Input from what is not known but if it is a proximity sensor it may be a Hall Effect Switch. In that case a small magnet moving nearby should be found somewhere.
The sensor receive 24VDC straight from the bus as supply voltage, that is consistent with a Hall Effect Switch.
The Z looking symbol on the other side means "crisp or abrupt switch of a binary nature" is either ON or OFF. In this case is most likely an Open Collector Output; compatible with a Relay as a load and typical of Hall Effect devices.
What bothers me is that can not see a diode across the relay coil.
Hall effect devices come in all packages. As small as a TO92 transistor but sometime are buried in an housing suitable for mounting easily and it the proper place.
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Re: Schematic Symbol questions

Post by curtis cutter »

I sent the picture on to my son who teaches robotics Pat. Maybe he knows.
Gregg
Just let go of it, it will eventually unplug itself.
Patio
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Re: Schematic Symbol questions

Post by Patio »

The sensor looks similar to this.
proximity sensor picture.jpg
proximity sensor picture.jpg (1.98 KiB) Viewed 5409 times
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John Hasler
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Re: Schematic Symbol questions

Post by John Hasler »

Might also be a reluctance sensor, in which case it will have a small magnet inside. Could be an inductive sensor. How old is the machine? Do you have a picture of it in place?
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Re: Schematic Symbol questions

Post by curtis cutter »

From my son:

Well, can't say for sure. Obviously, the symbols on the bottom of the box in the image (squiggly lines) appear to be temperature, like the temp gauge in a vehicle. Does temp sound correct for the context of the application?

The symbol on the upper right corner is much like I have seen before in digital output circuits, designed to deliver a positive-going output pulse at a certain point, often able to be adjusted.

Sounds to me like a typical thermostat, as opposed to variable output temp sensors. But I would be curious to see the bigger picture of the diagram...

However, the diagram printing is upside down, so it could be that the 24v signal comes IN at a pulse. What is the K16, those normally open contacts further up? Perhaps when the temp is at a certain point, AND when K16 is energized, then the (is that a relay?) with coil terminals A1 and A2 will energize?

Interesting..
Gregg
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Patio
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Re: Schematic Symbol questions

Post by Patio »

I believe it is a proximity type of sensor, that creates and interlock for another operation of the machine. There are two of these sensor in the machine. The one I am interested in, is buried, pretty much out of sight, the other is used to control the back and forth movement of the workhead table.
Here is a larger portion of the schematic.
20180910_182218a.jpg
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John Hasler
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Re: Schematic Symbol questions

Post by John Hasler »

Not a standard symbol. Zustellbetrag seems to mean "feed increment", if that's any help. The double tilde usually means "approximately equal".
Last edited by John Hasler on Sun Sep 23, 2018 7:34 pm, edited 1 time in total.
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SteveHGraham
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Re: Schematic Symbol questions

Post by SteveHGraham »

The forum at Allaboutcircuits.com can be useful. Just try to ignore snippy remarks from STEM kids with bad manners.
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Bill Shields
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Re: Schematic Symbol questions

Post by Bill Shields »

the schematic is not going to tell you exactly what the component is - unless the schematic has a parts list attached.

it is indeed some variety of proximity sensor telling the grinder to "feed at zero point" -> the sensor says "you are at the zero point"., but you are going to have to find a parts list or the actual component
Too many things going on to bother listing them.
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SteveHGraham
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Re: Schematic Symbol questions

Post by SteveHGraham »

Excellent point from Bill. A schematic is one thing, and a BOM (bill of materials) is another.

I would upload photos of the sensor, both installed and removed. Make it clear what it does in the machine itself, as in what moving part it detects. If it's a proximity sensor, tell us what gets close to it and how close. I assume it has a switch in it. Is it normally open or normally closed? It should be easy to determine that. If you can figure that stuff out, along with the dimensions, you ought to be able to find a new part that does the same thing.

I would still try Allaboutcircuits.com, though.

Another off-the-wall idea: contact the manufacturer of the machine.

I had to buy one of these things for a project, and it was surprisingly hard to find. It wasn't something you could just order from Mouser. Only one site had it.
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Atkinson_Railroad
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Re: Schematic Symbol questions

Post by Atkinson_Railroad »

It appears to be an IEC (International Electrotechnical Commission) symbol.

The burdensome task in determining what IEC publication number to reference to find the exact
meaning of the symbol is a big obstacle in learning what it may actually represent.

For sake of example, IEC 60034-8 is Part 8 of a document that defines terminal markings and electrical connections for rotating electrical machines. To view that entire document, one must pay for the publication and adhere to a strict license agreement.

A quick Google search found symbols that are fairly close to the one in the drawing,
but not that exact one showing the 3rd lead going to the symbol.

I also Google searched Zustellbetrag as John Hasler did and found references to setting grinding angles etc.

Not discounting Steve's suggestion of All About Circuits, but a more professional site such as
the Eng-tips forum would be better option to pursue.

https://www.eng-tips.com/

But even then... it would likely take an answer from someone who has access to the correct IEC document... and whether or not they would even be willing to share the information.

Here's fingers crossed, and good luck in figuring out its exact meaning.

John
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