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Author Topic: Does any one have the datasheet for a HP HEDS-7500 Optical Encoder??  (Read 13543 times)

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Offline Hood

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Re: Does any one have the datasheet for a HP HEDS-7500 Optical Encoder??
« Reply #20 on: August 06, 2008, 01:59:27 PM »
Just tested it out and Mach wont let the Axis DRO be changed while in feedhold so looks like it cant be done the way I was thinking :(

Hood
Re: Does any one have the datasheet for a HP HEDS-7500 Optical Encoder??
« Reply #21 on: August 06, 2008, 09:47:03 PM »
Bummer.  Well, at least the encoder will let me get back to zero.  I wonder if this could be a feature request? Adding simple closed loop support to Mach.
Re: Does any one have the datasheet for a HP HEDS-7500 Optical Encoder??
« Reply #22 on: August 08, 2008, 12:00:56 AM »
Would it be possible to tie the encoders into smooth stepper?

Offline Hood

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Re: Does any one have the datasheet for a HP HEDS-7500 Optical Encoder??
« Reply #23 on: August 08, 2008, 02:57:49 AM »
The SmoothStepper can accept encoder input  I think but it still wont allow compensation from them, it may change in the future but thats just a hope rather than a fact.
Hood

Offline Chaoticone

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Re: Does any one have the datasheet for a HP HEDS-7500 Optical Encoder??
« Reply #24 on: August 08, 2008, 06:14:13 AM »
dingbatca, Have a look at Rogers machine i think it is. He has an encoder interface board and a plug-in that will do what your looking for I think. If nothing else, it may help you see some posobilities.

http://www.rogersmachine.net/encoderinterface.html

Brett
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Re: Does any one have the datasheet for a HP HEDS-7500 Optical Encoder??
« Reply #25 on: August 08, 2008, 10:54:03 AM »
That was what I wanted to know.  So let me see if I get the order right.   Computer --> smooth stepper --> Rogers machine --> HobbyCNC?

Does the Rogers machine just stop when there is a missed steps, or does it correct for missed steps?

Offline Hood

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Re: Does any one have the datasheet for a HP HEDS-7500 Optical Encoder??
« Reply #26 on: August 08, 2008, 11:30:40 AM »
Ok first off thats the board I mentioned on page 2. Unless the plugin has been updated and Ron hasn't mentioned it on his site then it only halts on a following error.
 Setup is Mach to SmoothStepper (if you have one) then Rons board to port 2 and normal BOB on port 1. Can probably just have Rons board if dont have too many axis  for the I/O and use it as a BOB as thats what it is but with added functions.
 
Hood
Re: Does any one have the datasheet for a HP HEDS-7500 Optical Encoder??
« Reply #27 on: August 08, 2008, 12:03:31 PM »
Hood, you did mention it first, I was just not to sure what it did.  I am looking for a board that can correct errors, not just stop on them. I think I can do that with a plug-in.  At this point, and that cost $129, I think I will build my own close loop Mach plugin, if that is possible.  Currently know NOTHING about Mach's plugins, yet :-)

My CNC is a simple 3 axis, home brew CNC.  Nothing special.  Here it is, with out the dust shield covering the X and Y.  It was about 95% built at that point.
http://www.batbuilds.com/~adam/cnc_rev5/dsc05431.jpg

I do not have a smooth stepper, yet.  I think my CNC could benefit from one.  I am trying to keep the total cost for my CNC down. But, if something will allow my CNC to run for 10+ hours, with out jamming (think closed loop with correction) I do not mind putting in a good amount of cash. I think the current jamming problem is from the computer.  When I run slow, I have know problems.
Re: Does any one have the datasheet for a HP HEDS-7500 Optical Encoder??
« Reply #28 on: October 20, 2009, 01:27:35 AM »
I don't have the datasheet for these encoders but I do have the wiring details.  Is this still a proble out there?
email me on bobcohen@optusnet.com.au - I'd love to assist

Offline simpson36

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Re: Does any one have the datasheet for a HP HEDS-7500 Optical Encoder??
« Reply #29 on: October 28, 2009, 05:24:42 AM »
If you bite the bullet and go with real servo, you will have what you want . . a system that corrects for errors. That is essentially exactly how servo drives work; they constantly correct the following error. Some folks measure perfomance by torque or IPM or $. I measure performcnae this way:

Steppers: 3 to 5 almost identical parts before rehoming.
Servos: 50 identical parts without a restart, reset or rehome.

I have owned and run both. I'm 100% servo now and will never go back.
« Last Edit: October 28, 2009, 05:41:32 AM by simpson36 »