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Messages - mikecole

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1
CS-Lab / Re: Motor tunning with CSMIO/IP-A (PID) Trouble with encoders
« on: March 27, 2017, 12:48:25 PM »
Sorry Slovenec for that ambiguous answer...

For your machine, the way I understand it, your "encoder count" is 10k. The "steps per mm" is 10k / 5mm = 2000.

So your calculation is correct... Are you sure there is no reduction in the gears that connect the servo to the ball screw? It is common to have a 2:1 reduction. If this is true of your machine then your "steps per mm" number will need to be 10k / 2.5mm = 4000

Mike

2
CS-Lab / Re: Motor tunning with CSMIO/IP-A (PID) Trouble with encoders
« on: March 26, 2017, 05:32:36 PM »
The "steps per" value that CSMIO wants to know is "how many pulses should I expect when the ball screw rotates 360 degrees". The steps are normally supplied by an encoder on servo or ball screw shaft. In you case, using a linear scale you know that the precision is .0005mm. (ie. one pulse every .0005mm). Your ball screw moves the nut 5mm per revolution. So the correct "steps per" for your machine is 5mm / .0005 = 10k.

Mike

3
CS-Lab / Re: Bridgeport Romi lathe retrofit with csmio ipa
« on: March 13, 2017, 10:05:18 PM »
Hey Johnny,

Great to hear the gearbox looks pristine. Sounds like you've got a great lathe which will be worth the headache of upgrading the control system. The power supplies in these machine do seem crude but they work. Simple 60hz transformer, rectifier, huge caps... Curious about your servo amps. Do you have a web link for them?

Mike
 

4
CS-Lab / Re: Bridgeport Romi lathe retrofit with csmio ipa
« on: March 13, 2017, 12:22:54 AM »
Hey Johnny,

Perhaps Gecko are not the best choice... Did not notice they maxed out at 80vdc. I'm using Servo Dynamics amps... They are much more expensive however... Here's the link: http://www.servodynamics.com/product/1525-br-servo-amplifier/
American made so can't compete with the stuff from China on price. Great quality however... You still need to verify servos are good.

Here's the procedure I used to verify my servos and amps were good:

1.) I disconnected the belt from each axis. (not sure if this is possible for you?)
2.) I bypassed all the relays that implement safety and ready status logic so I could enable the amps. Remember once you enable the amps you could have an axis go wild so be careful!
3.) I used a 9vdc battery and a 1k pot to create a 0 to +9vdc input to the servo amp. This allowed me to verify that the servos would turn at an rpm proportional to 0-9vdc.
4.) Lastly, I reattached each belt to verify that the servos would move the table and Z axis. This too needs to be done with great care lest you run an axis past it's limit and damage your machine!

Hope this helps!
Mike



 


5
CS-Lab / Re: Bridgeport Romi lathe retrofit with csmio ipa
« on: March 11, 2017, 10:41:06 PM »
Hey Johnny,

Mike here again... Have you seen this thread from CNCZone: http://www.cnczone.com/forums/bridgeport-romi-lathes/289634-cnc.html

If I were in your shoes I'd at least try and use the DC Servos that came with the machine. My thinking is that if Bridgport/romi did a good job engineering the machine then the servos should be well matched to the machine. As per the post above, the Gecko drives are reasonably priced. If you go Gecko you'd want to go with the IP-S step/dir.

Mike
 

6
CS-Lab / Re: Bridgeport Romi lathe retrofit with csmio ipa
« on: March 06, 2017, 11:43:18 PM »
Good luck Johnny, Sounds like a fun project. Let us know how it goes... I can't find the " Chaosengineerings build thread" that you mention?

Mike

7
CS-Lab / Re: Bridgeport Romi lathe retrofit with csmio ipa
« on: March 06, 2017, 12:25:18 AM »
I found the csmio-ip/a docs to be quite good. You need a basic understanding of how a closed loop servo control system works. You will need electrical schematics for your machine that show servo, encoder and servo amp wiring. Lastly, you will need a VOM to do basic continuity testing along with perhaps taking voltage measurements. Sounds to me like you have the skills necessary to complete the retrofit....

As for running the lathe with a VFD... I don't see why it shouldn't work. The spindle will have an encoder/tachometer that tells the control how fast it's turning. The control should care less about how the spindle gets to that RPM.

Hopefully Hood will chime in here. I think he's done a lathe retrofit with the CSMIO-IP/A control.

Good luck!
Mike



8
CS-Lab / Re: Bridgeport Romi lathe retrofit with csmio ipa
« on: March 04, 2017, 11:34:31 PM »
Hi Johnny,

I don't have any experience with lathe retro-fitting but I can help with some general information based on my IP/A mill retrofit:

I'm using windows 7 (32 bit version) and my PC is NOT connected to the internet. Like you I was fearful of the "automatic updates". Mach 3 is running fine on this config. All gcode gets to the mill via a USB thumb drive. Admittedly old school but I like that my mill is safe from all the internet distributed virus and malware crap.

As for running the lathe with a VFD....I run my manual lathe (Southbend 16 x 6) with a VFD because it's 3-phase and I don't have 3-phase in my home shop. Threading is not an issue since the lead screw or cross feed still runs at a fixed fraction of the spindle irregardless of motor RPM. The head on my lathe is belt drive so I'm a big fan of using the VFD to get the spindle speed I want. I find I run on the middle pulley and I almost never use the back-gear. My work is usually 6061 or A36 and I'm not ever trying to mass produce anything...

As for your particular retro-fit... I'd encourage you to go for it if you have a known good lathe (minimal backlash) with an antiquated CNC control. You should verify that your servos, encoders and servo amps are in good working order before proceeding with the IP/A. If you find you need to update your servo amps this this may lead you down a path towards going step/dir rather than analog... Also, encoders should be 500line or better.

Hope this helps!
Mike





9
CS-Lab / Re: CSMIO-IP/S or CSMIO-IP/A for a servo controlled router
« on: February 26, 2017, 12:06:07 AM »
Hi Jorge,

I believe that the only reason anyone would choose the IP/A control is if they have existing servo amps that require analog control (+/- 10vdc). In your case, if you are choosing new servos and amps you will want to go with the more modern step/direction. I am not aware of any drawbacks with step/direction as compared to analog control. If you are selecting new servo motors and amps then consider AC or BLDC over brushed DC servos. Why have brushes in your servos that can wear out? I am not sure about cost however....

Good luck!
Mike

10
CS-Lab / Re: IP-A and Servo drives, voltage matching...
« on: November 07, 2016, 04:07:06 PM »
Hmm,

Well your troubleshooting instincts are good... Testing the tach signal should be easy, it's likely a +5vdc square wave, one pulse per rev so 3khz = 3000 rpm. 1.5khz = 1500rpm. Probe at the connection to the amp.
It's good that the servos run 3k @10vdc but it would be reassuring to know they run at 1500 rpm at 5vdc. This will at least tell you that there is a linear relationship between control voltage and RPM since this is what the IP-A expects.

I agree with you, this really sounds like a problem with the amp parameters... Can you even be sure that you have connected the tachs to the right pins given the poor docs?

Good luck!
Mike






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