P1-Engineering schreef: ↑14 aug 2023 20:11
Adding a capacitator made a big difference for me
What difference did it make? Did it solve an issue you suffered without? Are you also using the leadshine PSU's? I'm not using leadshine PSU's, yet push it pretty hard without issues. (either with the JMC and the OMC servo's).
In the case of Mikko, I would have replaced the PSU's. We've exchanged some emails/whatsapps in the passed months, and the PSU isn't suited for the task in my opinion. (either that or the cabling is wrong) With maximum acceleration/speed the motors stall and throw a voltage related issue if memory serves well. The added capacitors shouldn't be required. Perhaps some odd resonance occurs at settling speed of the motor tripping voltage of the PSU again causing the motor to reach an over or undervoltage limit, but not enough to trip a real error.
My first guess, based on the previously stated issues, is the meanwell PSU.
If you haven't tried Kjelts tip (place the capacitors as close to the motors as possible) try that first. It could help.
The Z-axis motor was throwing an alarm often, over-current and another one which could be related to input voltage. To get rid of it I turned the speed down to max of 2500mm/min and acc. to 400mm/s or something. After fitting the capacitator was able to go back to 5000mm/min and 1000mm/s. Without changing anything else.
Also a 600 watt meanwell PSU, same as the TS, from Sorotec, driving 3x 180watt JMC's.
Now I'm thinking it would be better to have a PSU per motor or a big transformer type which is more suited for the kind of loads it is seeing.
It is a very big difference but i stil have one HP ESP120 power supply for sale.
This power supply is brandnew and gives just over 50V @ 60 Amps, with a simple modification the voltage can be modified to abouth 45VDC.
This power supply is very robust and very stable in output voltage.
Some update. Some conclusion and this point, the problem is NOT related to these things:
- Spindle (tried without)
- VFD (tried without)
- it's not g-code, same shocks occurs also when jogging
- parameters (tried quite "soft" autotune parameters)
- mechanical (ballscrew and rails moving smoothly)
Also found out that dual Y-motors maybe does not generate these shocks after all. So there is something between X and Z. When X is moving, Z creates these shocks even Z motor is not moving.
X and Z are feeded by the same PSU. Dual Y motors does have their own PSU. Maybe I next try to swap PSU's or try without X motor.
Again few updates. Tried different pc, no effect. Also noticed that Z servo is making shocks also when just jogging that axis. So I think need to focus now more to Z motor cabling and grounding.
I might have now a solution. I bought a cheap unshielded(!) Cat6 cable and wired it directly from motor to cabinet. At least after 5minutes of jogging I couldn't get these shocks again. Need to do more tests to ensure this.
Then you had a ground loop through the CAT6 shield. Check the suppliers manual to see if a shielded CAT cable is recommended. If so, check the ground cable(s). They should be tick ( 6 mm2). Also ground connections on aluminium need a toothed washer.
There are only 2 limits, the sky and your imagination
mkuivamaki schreef: ↑17 aug 2023 18:39
I might have now a solution. I bought a cheap unshielded(!) Cat6 cable and wired it directly from motor to cabinet. At least after 5minutes of jogging I couldn't get these shocks again. Need to do more tests to ensure this.
Fact that this makes this difference tells me that you are not control this signal in a differential way.
The input of the servomotor is normally a LED from an opto-coupler so you should have a signal current going via a wire into the LED and one coming out the LED which goes back to the control board. Those 2 wires should be twisted to each other to eliminate EMC signals from this wire to other devices AND also to eliminate EMC signal coming from other devices to disturb you control signal.
If you put a ferrite around this wire it should have no or minimal effect or gives better results.
I am very sure somewhere in the connection of the control signal is a miswiring, most likely in the ground connection.
If the shielded Cat6 cable gives a problem then cut the ground on one of the two sides, then you still have shielding but no ground loop.
I continued with troubleshooting this problem. My earlier post was not solution afterall. It was not the cat cable. I was getting shocks during long cnc program.
So today I tried to disconnect the Z motor power supply. Turned machine on and jogged X axis for a while: I was still getting these shocks! So it was not only the Z motor, all of the servos are making thesw shocks at the same time.
So could be messing up the signals? Any ideas what to try next?
mkuivamaki schreef: ↑03 sep 2023 17:31
I was getting shocks during long cnc program.
If it is only during a long CNC program run, maybe something is getting hot and shuts down. That could be a power supply, the servo driver, but also the mains connection, outlet, extension cord, even the (main) circuit breaker.
There are only 2 limits, the sky and your imagination
Was not the line filters. At least I see they were unnecessary
Not much things to test anymore. Maybe the power supplies are not ok for this use. But I see many uses Mean Well PSP psu's with JMC's
I could still test to put those capacitors on the motor side power connector and see does it help.
