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Author Topic: RPM and counting ?  (Read 12571 times)

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Re: RPM and counting ?
« Reply #10 on: April 02, 2010, 01:10:50 PM »
There is a small strip of steel that has been screwed onto the spindle so it reads each revolution.  I have the pins configured properly as far as I know.  As I rotate the spindle the sensor is picking up the strip mounted on the spindle so I know the sensor is working.  It has a little LED on the back of it that lights up when the spindle plate passes.  The problem is that the signal is not getting into Mach3.

As I said before I am using 2 different power supplies, is this a problem?  I am using a separate PC power supply for the spindle sensor (12V) and I am using my driver board on its own.  The driver board does not have a 12 volt output, thats why I need the PC power supply.  My question I guess is does the ground need to be shared between the 2 power supplies for this setup to work?

I dont have my sensor info in front of me but I will post it ASAP.
Re: RPM and counting ?
« Reply #11 on: April 02, 2010, 04:40:05 PM »
To add, the sensor I have is a proximity sensor.  Model number IS12-Y4-N-OC-DC.  I looked up the specs here: http://eurospecdirect.com/DataSheet/cs12_sensor.pdf  It looks like either of the NC or NO wires, which ever I am using, needs to be grounded.  It also looks like the sensor can take 24 volts so that means I can use my driver board as it has a 24 volt output for a fan.

Offline RICH

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Re: RPM and counting ?
« Reply #12 on: April 02, 2010, 06:07:35 PM »
Hmm....., I am not sure on this, there are four wires. The Blue / conn 3 is ground and would go back to your power supply ground.
Now when it senses the strip, you have two choices for an output to Mach, as the internal switch can be opened or closed so that is conn 4 or 2 and one of them would be used an input to Mach. I guess the difference would high to low or low to high voltage change but that can be addressed in configuration. Check the voltage output from connection 4 or 2 and see what the swing is ie; 0 - 24v ? I would limit it to 0 to 5 volts.

I see Hood is in here, how do you see it?
RICH
Re: RPM and counting ?
« Reply #13 on: April 02, 2010, 06:22:59 PM »
Do you think that it matters that the ground from my driver board and the ground from my sensor power supply are not shared?  The driver board is powered by its own supply and the sensor is being powered by a converted PC power supply.

Offline RICH

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Re: RPM and counting ?
« Reply #14 on: April 02, 2010, 06:32:10 PM »
As i have been informed......
You should take the circuit ground back to the supply source where the positive came from. If you take it to some other ground that ground may be at a different potential as compared to the one that supplied the power. 
Now does it matter? Well sometimes no and sometimes yes, you can try and see how it goes!
RICH
Re: RPM and counting ?
« Reply #15 on: April 02, 2010, 06:39:39 PM »
I see your point Rich.  I also gathered from the diagram that one of the 4 or 2 wires needs to be grounded back to the negative.  Well that was not the case in my setup.  I have one of those wires terminating in the 15 port.  Should I run a jumper wire from the 15 port back to the 12 V power supply ground to complete the circuit?  I was thinking that is why I am not getting a reading.

Offline RICH

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Re: RPM and counting ?
« Reply #16 on: April 02, 2010, 07:13:15 PM »
conn 1 / browne wire -  gets the supply from the power source for the circuit ( + )
conn 3 / blue wire - is connnected back to the supplies ground as that completes the circuit ( - )
conn 2 or 4 - one will go to an input pin so Mach will see the pulse
The one you don't use should be left alone as no current will flow through it since the circuit is not completed.
That's what i get out the info you posted.

RICH
Re: RPM and counting ?
« Reply #17 on: April 02, 2010, 07:18:58 PM »
Yeah, thats how I got it hooked up Rich and Mach3 wasn't seeing anything.  I will do like you said and see if there is any voltage coming out of the 2 or 4 wire when the spindle LED activates when I get home.  If it is more than 5 volts then perhaps Mach3 does not see it.
Re: RPM and counting ?
« Reply #18 on: April 02, 2010, 09:29:00 PM »
So Rich, I hooked up the sensor to the 24 volt supply on my driver board.  The output of the the NC wire when the sensor is activated was ~22volts, a little high.  So I got a small regulator from Radio Shack and stepped the output down to 5 volts exactly.  I checked pin 15 with everything powered up and spun the spindle till the sensor LED came on and the pin was getting 5 volts exactly.  But when I went in the Mach 3 Diags the LED was not lighting up.  I tried this on both the Timing option and the Limit Option.  Do I have something configed wrong in Mach?  I tried reading in the manual to no avail for setup info, perhaps I missed something.

Offline RICH

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Re: RPM and counting ?
« Reply #19 on: April 02, 2010, 10:28:21 PM »
You have a light on your sensor which which should come on when it just sees the tab, and it should just stay on until you just get past the tab and then it  should go off. In diagnostics and if the signal is sensed by Mach via the input, then you will see the same kind of thing, namely the index led will will turn on and then as you rotate the spindle it will turn off until the tab is seen again.

If you measure the voltage  out of the sensor conn pin 2 or 4 ( which ever one your are using ) to ground , you will see the voltage change from a low value to a high value. The low may be .8 volts and the high may be 4.9 volts, but there is a difference between the low and the high. That difference, in order to change the state at the PP from low to high, needs to be around 3 volts. If that is not the case then you may  not be able to change the the state of the signal from a high to a low. It's just a square wave _----_----_     on so long and off so long at a low and high voltage. So lets make sure that is correct first. Since you are using 5 volts there may be enough of a voltge drop across the internal circuitry of the sensor such that you are only getting 3 volts out say and which may be insufficient to change the pp state from low to high. If thats the case try adjusting your feed voltage to say 10 volts and see how it goes as 10 volts may be the min voltage required for that sensor.

Attach your xml file you are using and we will have a look at your settings.

RICH