OT Electrical - Adding a panel mounted tach to lathe?

[HoosierBuddy]

Hey guys,

This is a bit beyond garage lighting...but is definitely garage/electrical related...so maybe someone can help.

I'm building an electrical control box for my lathe. While considering this, I thought "How cool would it be to add a panel mounted digital tach display to my control box?"

So...that thought led me to Ebay where a place in Ireland is selling a cheap Chinese panel mounted digital tach for about $40.

http://www.e3b6a5y.com/365/WiringDiagrams/365um6150rpfTACHO.PDF

According to that, the panel mounted tach requires a sensor to give it input. It even says "PNP / SN04-N Sensor" on the wiring diagram. Of course...they don't include that sensor in the box.

Anyone have a clue on what that means? Where you can buy one?

If this could be done for not a lot of money, I'd like to try it.

Phil

 

[1Garageman]

I did some research for you on this. I found it on about 50 webpages. I think 49 of them where in a different language. This is the only one I found that was in English.
It is the second item down.
http://www.yoguai.com/trends/ds_en.html
Hope this helps and good luck.
And we must see some pics when it is done!

 

[Falcon67]

Depends on the input. Might be able to make use of the info here:
http://www.shumatech.com/web/products/dro-350/add-ons

 

[Torque1st]

According to the manual just about any type of trigger will work:
NPN, PNP Sensor of IR or Coder Switch/Pulse Input


The section of the manual that reads:

If there is not a Push Height Resistor built-in the sensor (NPN), an external resistor of about 5.1 Kohms must
be added between POSITIVE and SIGNAL. For a PNP sensor, an external resistor of about 5.1 Kohms must *
be added between GROUND and SIGNAL.
Has lost something in translation to Engrish

It should read something like this:

If there is not a Pull up Resistor built-in the sensor (NPN), an external resistor of about 5.1 Kohms must
be added between POSITIVE and SIGNAL. For a PNP sensor, an external resistor of about 5.1 Kohms must *
be added between GROUND and SIGNAL.

Almost any sensor will work for this device. Let us know what you find that you think may work.

 

[HoosierBuddy]

Engrish

::

I had the thought yesterday that dozens of layed off american factory workers should be able to get full time jobs translating engrish translations of chinese installation manuals to american.

Harbor frieight suppliers ALONE could tie up several dozen people for years.

...

I'm waiting (with little hope) for the people in Ireland to point me to a sensor they know will work. Sounds like this is doable though. I will likely go ahead and buy the display so I can incorporate it in the panel and piece together the rest of it as time permits.

Phil

 

[JamieK]

What about something like this?

http://www.sendec-products.com/index.php?option=com_content&view=article&id=110&Itemid=136

 

[1Garageman]

What about something like this?

http://www.sendec-products.com/index.php?option=com_content&view=article&id=110&Itemid=136

That is pretty nice, and it is in the $80 price range. Nice find

 

[Torque1st]

What about something like this?

http://www.sendec-products.com/index.php?option=com_content&view=article&id=110&Itemid=136

That setup would work.

For sensors that work with the original display look for "proximity detectors" or "proximity sensors" with either a PNP or NPN transistor output with the proper frequency range to match your speeds. Prox sensors detect metal.

You can also get optical sensors that will react to a reflective spot of white paint or a flat on a shaft.

What you are looking for on the machine is a keyway, flat spot, hole, or some other distinguishable characteristic that is apparent once each revolution.

Which type to use will depend on the machine configuration.

 

[sixgun]

Hello, new here. I have recently purchaced one of these same tachometer gadgets. I interpreted that any npn or pnp photoelectric/proximity switch could be used as long as it has a 5.1 Kohm resister between the signal and positive/ground ( respectively ) leads. I am in the process of purchacing a resister as I can not find my bag of spare resisters at the moment. If this does not work I am thinking of purchacing anoter type of tachometer to work with. So far I have a little over 40.00 in the set up. Investigation continues.