LinuxCNC Support Forum :: Topic: retrofit on EMCO PC turn 55 (10/14)

andypugh OFFLINE Moderator Posts: 4140 Thank you received: 141 Karma: 130	jrkeat wrote: I actually just found them. They are "front style terminal blocks" or "Euro style terminal blocks". I had despaired after looking through most of the connectors in the DigiKey catalogue. Be careful ordering, they come in a range of pitches, and 5mm won't mate with 5.08mm (0.2") nor will 3mm mate with 1/4".
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Re:retrofit on EMCO PC turn 55 02 Jul 2012 06:10 #21491

jrkeat OFFLINE Junior Boarder Posts: 21 Karma: 0	andypugh wrote: My shopping list would probably be Intel BOXD525MW $80 8 GB SATA DOM $40 60W PicoPSU $30 How would you install th OS on this system?
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Re:retrofit on EMCO PC turn 55 02 Jul 2012 06:49 #21494

andypugh OFFLINE Moderator Posts: 4140 Thank you received: 141 Karma: 130	jrkeat wrote: How would you install th OS on this system? From a USB stick created using the Ubuntu startup disk creator and the LinuxCNC LiveCD image (In fact I have done so twice)
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Re:retrofit on EMCO PC turn 55 19 Jul 2012 06:18 #22185

jrkeat
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For the mesa board, the 7i76, due finally to arrive today, I seems like there is only one voltage used for communications, and that that voltage is 24v. My system, however, has a mixture of 5v and 24v inputs and outputs. The differential stepper lines have an impedance of only 500 ohms, for example, so they require 5v, and were driven by 5v in the original.

What would be the standard circuits for doing the voltage conversions? In particular, what would be a standard way to convert the inputs from 5v (the spindle and tool changer signals are actually 3.6v) up to 24v?

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Re:retrofit on EMCO PC turn 55 19 Jul 2012 07:22 #22189

PCW OFFLINE Moderator Posts: 1671 Thank you received: 87 Karma: 116	First, the 7I76s step and dir signals are differential 5V (they are not part of the field I/O) Can you describe the spindle and tool changer signals, that is, their direction and function?
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Re:retrofit on EMCO PC turn 55 19 Jul 2012 08:16 #22199

jrkeat
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PCW wrote:

First, the 7I76s step and dir signals are differential 5V (they are not part
of the field I/O)

That's great!

I haven't studied the spindle and changer circuits, but I'll tell you what I think I know without having them in front of me. There are two signals for each. For the spindle, there is a pair of optical encoders, one going on and off perhaps 100 times per revolution and one that goes once per revolution. These are debounced, and alternate between 0 and 3.6V. The tool changer is similar, with one firing for each of the 6 tools, and a second firing once per revolution.

Last Edit: 19 Jul 2012 08:17 by jrkeat.

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