Spindle index

More
29 Jun 2017 20:04 #95187 by russkinch
russkinch created the topic: Spindle index
Hi. My CNC lathe is finally completely finished. I have used it to machine some pistons and it works great. Thanks to everyone here for their help. One final thing is to get screw cutting sorted. I have an index plate on my spindle. 60 holes and 1 index. 2 opto couplers running on 5v to BOB. I can get it to register a spindle speed on the axis display but only up to 212 RPM, anything over that and the display reads 0. I am not sure if I should have a resistor connected in line. Please forgive my ignorance, I am a classic car and bike engineer, not electrical. This project was a HUGE learning curve for me. MY opto couplers are Infrared Slotted Speed Measuring Sensor Optocoupler(LM393). I am not sure if there are correct. I have my HAL file if it helps. As a result, I cannot screw cut yet, nor get a display of speed. I am only using the M3 S.... to tell the machine the speed with no display if it is accurate.
More
04 Jul 2017 10:58 #95349 by andypugh
andypugh replied the topic: Spindle index
I guess you are using the parallel port and a software encoder counter?

212 rpm = 3.5 rps = 212 Hz at the opto. That's 4.7mS per pulse, so should not be anywhere near any actual limits.

I think we might need to see the HAL and INI files. Is there any filtering on the BoB? what is the specified response time of the optos?
More
04 Jul 2017 15:44 #95361 by russkinch
russkinch replied the topic: Spindle index
Hi Andy,

I am not sure if there is filtering on the BOB. Its a Mach3 BOB from E-Bay. Everything else works great. I have attached my INI and HAL files. Many thanks.

File Attachment:

File Name: lathe.hal
File Size:4 KB

File Attachment:

File Name: lathe.ini
File Size:3 KB
Attachments:
More
05 Jul 2017 22:38 #95416 by andypugh
andypugh replied the topic: Spindle index
You have a base-period of 115000 which seems very high. But still not high enough to explain the problem.

115uS @ 60 slots x4 for quadrature is 36 rps. That's 2170 rpm.

Do you have access to an oscilloscope? You might need to have a look at what is happening at the parallel port pins.
More
08 Jul 2017 06:06 #95492 by tommylight
tommylight replied the topic: Spindle index
Halscope should show what is going in to the paraport, i think it will not look nice since BOB's are increasingly getting worse, the cheap ones.
You can wire the encoder directly to paraport if it is a 5V one, it should work much better that way. You can also power it from a USB port.
More
11 Jul 2017 15:28 #95673 by russkinch
russkinch replied the topic: Spindle index
Hi. Thanks. I checked hal scope and it picks up spindle-index and also spindle-phase-b. Are these the correct terms. I know index is the single hole per rev, the 45 holes should that be phase-a or phase-b?. The scope image of spindle-index looks like a rectangle with the top slightly smaller than the base. I have no idea if this is correct as I am not an electrical engineer......no way clever enough.
More
11 Jul 2017 16:22 #95676 by Todd Zuercher
Todd Zuercher replied the topic: Spindle index
Yes, that is what it should look like. The A and B are reading the same holes in the encoder, but because they are in slightly different positions, the toothed pastern they produce on Halscope should be 90 degrees out of phase with each other (half a tooth difference between them).
More
18 Jul 2017 16:10 #95987 by russkinch
russkinch replied the topic: Spindle index
Hi,
I have been struggling all this time with this. I still cant seem to thread. It starts the cycle and then sits there waiting. I have looked in my hal scope. The index pin has a nice square shape, but there is nothing for phase a. I am only using a single optocoupler on the index and a single on phase a. but this is got me stuck. can anyone assist. please please please
More
18 Jul 2017 16:33 #95993 by andypugh
andypugh replied the topic: Spindle index
I was threading last night and had the same symptom because spindle-at speed was not being set.
You will also get this if the Z axis can't run fast enough to synch with the thread.

But, if you say that you can't see the A-phase, then that is probably the problem.

Which signal are you halscoping to look for the A-phase?

Does motion.spindle-revs show an increasing value?
More
18 Jul 2017 16:43 #95997 by russkinch
russkinch replied the topic: Spindle index
Hi,

No, in hal meter motion.spindle-revs shows a 0 above it
Time to create page: 0.088 seconds
Powered by Kunena Forum