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21  Mach Discussion / General Mach Discussion / Re: Noise Problem on a large machine on: November 08, 2014, 01:11:18 AM
Thanks guys. Will check the points you're suggesting.

Just to make it clear - I forgot to mention it - the problem with the monitor going off happens both when the Estop is depressed and upon its release. Anyway, the problem with the monitor bothers me least at this time. What really bothers me is the steppers moving on their own while not even an inductance motor running, starting or stopping. When this happens, disconnecting the USB cable from the Smoothstepper stop it.

Dan
22  Mach Discussion / General Mach Discussion / Re: Noise Problem on a large machine on: November 07, 2014, 03:30:47 PM
1. To be more accurate, it's not bare capacitors, but rather a self contained dedicated filter with caps and resistors in series. These are usually used across contacts. Anyway, using it or omitting makes no difference.
2. Checked and, no fault there.
3. Also checked to be OK
4. The star point doesn't go to solid earth ground. It goes to the electric outlet in the same cable with the 3 phases, and the ground wire is only 2.5mm in diameter. I will try connecting the star point metal construction of the building.

Dan
23  Mach Discussion / General Mach Discussion / Noise Problem on a large machine on: November 07, 2014, 09:10:56 AM
Built a 4.5m cylindrical grinding machine. The control console is a attached to the carriage and travels with it along all the machine length. The machine uses steppers and has 4 axes. Cables running to the carriage (in a single chain) are 10m long - 2 cables to the steppers (shielded and grounded at the electrical cabinet), 2 cables to two 3 phase inductance motors (shielded and grounded a the electrical cabinet), a VGA cable to the monitor on the console, a THICK ground wire to the console.

The electrical cabinet has 4 Gecko stepper drives, a mini PC, USB SmoothStepper, VFD and a few relays and contactors. SmoothStepper has a separate 5V power supply, but also tried to power it from the USB. The USB cable shield is grounded only at the PC. Everything is grounded in the cabinet to a single star point. and EMI filter is used between mains and monitor, PC, 48V PSU and 5V PSU. The contactors have capacitors over the contacts.

PROBLEM 1: An E-stop button on the console cutting 230VAC to a three-phase contactor in the electrical cabinet. The contactor cuts off power to stepper PSU and VFD. Hitting the E-stop causes the monitor to turn off for a couple of seconds and then it returns back. Disconnecting the stepper PSU from the relay and leaving on ly the VFD still causes the same.

PROBLEM 2: Turning ON either of the two 3-phase motor - VFD or direct, causes the monitor to turn off for a couple of seconds. Turning off the motors causes the same.

These problems, I think, are due to to bad VGA cable (although shielded).

PROBLEM 3:  At times the steppers (particularly one of them) start moving on their own. The 3 phase motors are not running at this time. Disconnecting the USB cable from the SmoothStepper stops it. I am not sure, but I thing that disconnecting the VGA cable from the PC also stops it. This is the most significant problem.

Any thoughts?

Dan
24  General CNC Chat / Show"N"Tell ( What you have made with your CNC machine.) / C.E. Johansson Roundness Tester Retrofitted on: October 13, 2014, 06:13:21 AM
Retrofitted this old machine using Arduino. Here is a video:

http://youtu.be/UTYC6Tr2C_M

Dan
25  Mach Discussion / General Mach Discussion / Re: Servo for lathe spindle ? on: October 07, 2014, 05:05:05 AM
Glad you have it working now. Generally speed mode is preferred for CNC machines.

Dan
26  Mach Discussion / General Mach Discussion / Re: Servo for lathe spindle ? on: October 03, 2014, 10:07:47 AM
Glad to hear it was an easy fix for you.

The DAC offset is the setting that should fix your drift issue. Hood is more experienced with analogue, and I believe he will be of greater help as to why it doesn't solve your issue completely.

Dan
27  Mach Discussion / General Mach Discussion / Re: Servo for lathe spindle ? on: October 01, 2014, 07:54:49 AM
Sounds good!

Dan
28  Mach Discussion / General Mach Discussion / Re: Servo for lathe spindle ? on: September 30, 2014, 07:10:19 AM
Forgot to say. You can measure the output signal from the encoder, if you see it's a good 5V then a line driver may not be necessary.

Dan
29  Mach Discussion / General Mach Discussion / Re: Servo for lathe spindle ? on: September 30, 2014, 06:09:03 AM
You can try connecting the signals directly, but usually encoders output weak signals so a line drive would be preferable:

http://www.cnc4pc.com/Store/osc/product_info.php?products_id=337&osCsid=53062d4f014880b38fc29ac5affa980c

Dan
30  Mach Discussion / General Mach Discussion / Re: Servo for lathe spindle ? on: September 30, 2014, 03:47:46 AM
I didn't read all your posts from yesterday, so don't know how you arrived at the conclusion that it is the encoder outputs from the drives that are not functioning, but connecting the encoders directly to the CSMIO should work I think. You will need to use a line driver and supply 5V to the encoders.

Dan
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