Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: jab_814 on August 05, 2012, 06:22:30 PM

Title: Index problems
Post by: jab_814 on August 05, 2012, 06:22:30 PM
Hi guys ,
My problem is my index is showing the rpm eradically. I call for s800 and it gives me anything from 150 to almost 1000 it stays somewhat steady at 350 .
I am using pokeys 56e for the input on 7 for index
The sensor is a Pmdx 170 slotted optical sensor
I have a 1100 ohm sensor from v+ to true . I check at input 7 with a multimeter and I am getting 5 volts when it pulses and zero when interrupted . Index debounce
 is at zero . My slotted disc is 4 inch and my slot is .375 . I have my spindle ratio at 1 and my speed is set at 200 to 4000 rpm . I hope i gave enough info , thanks

Title: Re: Index problems
Post by: RICH on August 05, 2012, 06:47:02 PM
Try a higher debounce, go in intervals of say 5 and see if it improves. There is a formula for calculating the width of the slot which you can find in the Mach3  Manual. I remember that  a wider slot is ok as compared to a narrower one. Not familar with using the pokeys which could be influencing
the readout. I am sure others will reply.

RICH
Title: Re: Index problems
Post by: jab_814 on August 05, 2012, 09:18:21 PM
Thanks rich , however the debounce seems to have no effect on the pulse. Also I notice in diagnostics that the index is not pulsing at the same constant rate as the led on the optical sensor . Does this matter . It seems to be also erratic . I also have tried this on a pmdx 122 bob. It had the identical results.
Title: Re: Index problems
Post by: Hood on August 06, 2012, 02:56:39 AM
Index debounce is unlikely to make any difference if you are using the PoKeys as that will be handled by the plugin. Have you tried changing the active state of the Index input? Also with regards to the LED on Diagnostics page, that is of no concern as the refresh rate of the screen is way to slow to show the LED in real time, it only serves as an indication that the signal is getting through.
Hood
Title: Re: Index problems
Post by: jab_814 on August 06, 2012, 08:34:11 AM
Yes , I have tried inverting the signal in the pokeys plugin as well . I have however just remembered that I never grounded the shield for the cable in the control . I will try that and let you guys know . I might even put a scope to it to see if there is noise .
Title: Re: Index problems
Post by: jab_814 on August 07, 2012, 10:54:36 AM
Ok I grounded the shielded cable and still have the same problems , it did however help a bit . I will try to get a scope to it to see clean signals to the pokeys .
Title: Re: Index problems
Post by: Hood on August 07, 2012, 01:41:21 PM
Just to confirm, you are using the PoKeys as your motion controller?
Hood
Title: Re: Index problems
Post by: jab_814 on August 07, 2012, 01:48:10 PM
No I am using it for inputs
Title: Re: Index problems
Post by: jab_814 on August 07, 2012, 01:48:44 PM
I am using a pmdx122 bob
Title: Re: Index problems
Post by: Hood on August 07, 2012, 01:52:38 PM
Ok so you are just trying to input the Index via the PoKeys but have Mach connected to the Parallel Port for motion control?
If so then I have my doubts whether that will work as there will be a delay from the plugin to Mach.
Can you not connect directly to the BOB rather than go via PoKeys?
Hood
Title: Re: Index problems
Post by: jab_814 on August 07, 2012, 02:29:53 PM
As of now no all inputs are used , I currently have the A and B for mpg , one for limits , and one for an optical sensor for a home/ limit for the z . Do you think I could slide the a and b over to the pokeys or even the home and limit switch .
Title: Re: Index problems
Post by: Hood on August 07, 2012, 02:32:57 PM
I would definitelky leave the Home/limits on the parallel port so possibly the MPG would be the one to change over. I have not tested the MPG on the latest PoKeys plugin but I think it works reasonably well.
Hood
Title: Re: Index problems
Post by: jab_814 on August 10, 2012, 03:23:04 PM
It works now, I did what hood mentioned and that corrected the problem. Thanks hood I appreciate your response .
Title: Re: Index problems
Post by: Hood on August 10, 2012, 03:38:16 PM
Glad you got it :) Did you hook the MPG via the PoKeys? If yes does it work well
Hood
Title: Re: Index problems
Post by: jab_814 on August 10, 2012, 06:45:11 PM
Um I haven't got it to work yet . Didn't spend much time . But what I did was enable fast encoders , pins 1 A , 2 B. but I didn't get it too work . Don't know how to tell Mach 3
Title: Re: Index problems
Post by: Hood on August 10, 2012, 07:10:49 PM
I did try it out with the Alpha plugin a while back but its totally different now, will have a look and see what you have to do but think its all plugin and you dont have to do anything in Mach.
Hood
Title: Re: Index problems
Post by: Hood on August 10, 2012, 07:24:26 PM
Kind of looks like you would just select the MPG DRO in the drop down list on the plugin page.
Hood