Acorn + GR214V erratic motor behavior during power up and down (RESOLVED)

[Eric]

I am running Acorn with 4 Gecko GR214V at 60V which is a separate power supply. The issue that I'm seeing is that the erratic motor movements are automatically triggered during power up and power down, which both power supplies turned on and off at the same time. Once system completes boot up process, it seem to work just fine.

Similarly to viewtopic.php?f=60&t=6971&start=10, I've used double shielded cable and power supplies are connected correctly, but I'm still seeing this erratic movement with loud snapping sound during power up and down cycle, and couldn't pin point what is causing this behavior. So, when I turn on the controller first and then turn on 60V power supply during power up and in reverse order for power down with different on/off switch then it seems fine.

The question is whether:

• If there is an official or proper power up or down sequence and what I'm observing is an expected behavior?

• If I'm missing anything in terms of making sure that this kind of erratic motor movement does not happen?

• If the official wiring diagram for GR214V (https://www.centroidcnc.com/dealersuppo ... 113.r2.pdf) is really correct, meaning that Acorn should have been utilizing ENABLE pin, so that such erratic behavior can be prevented?

I appreciate any response or helpful pointers in advance. Thanks!

[Gary Campbell]

When shutting down, do the following:
Engage ESTOP switch
Shut down CNC1`2 software
Turn off power to controller

When powering up:
Power up control
Start CNC 12 software
Disengage estop

[Eric]

Gary, thank you for your response! I actually tried that and it didn't really change the behavior much unfortunately. Also, ESTOP is already engaged when the controller powers up isn't it? Let me know if I'm missing anything. Thanks!

[Gary Campbell]

The reset (soft estop) may be, but I am referring to the physical estop as it actually has more internal functions

[tblough]

Acorn has a NoFaultOut output that it turns on when it's ready to begin. This should be routed to a Master Control Relay that switches on the motor power for the machine. Here's an example:

https://centroidcnc.com/dealersupport/s ... 190.r1.pdf

[ShawnM]

Gary, thank you for your response! I actually tried that and it didn't really change the behavior much unfortunately. Also, ESTOP is already engaged when the controller powers up isn't it? Let me know if I'm missing anything. Thanks!

Just to clarify Gary's response, the "RESET" button on the VCP is NOT an ESTOP. They both have completely different functions. This is a big misnomer for many new users.

[Eric]

Gary and ShawnM,

Ah, thank you for the clarification and it makes sense now! At this point, I feel that the erratic movement during power up is somewhat reasonably as it is pretty minimal, but not during power down. After doing some more testing, I think it is mainly due to that 60V power supply has larger capacitor, so I feel like the best bet is to utilize contactor as Tom suggested as it cuts the power immediately. So, I'll try to get that working and report back. Thanks!

Cheers,
Eric

[Eric]

Tom,

On a second thought, I probably got the estop contactor wrong in my scenario. Here is what I'm thinking after looking at the schematic:

If I'm not mistaken then it seems the 3 poles for incoming motor power supply is AC (probably not necessarily), which means motor power will be connected only after controller boots up completely and that is great. However, during power down it will not cutoff the capacitor power immediately hence the issue might remain. So, perhaps what I could do is to use the contactor poles for connecting the DC output of the motor supply using the contactor?

Also, I could probably take advantage of extra pole to wire VFD as shown in https://www.centroidcnc.com/dealersuppo ... 166.r1.pdf and per the discussion in viewtopic.php?f=60&t=9869&p=84863&hilit ... tor#p84863.

Please let me know if any of this doesn't sound like a sane approach.

Thanks!

[tblough]

You want the motor power (not logic power) for your VFD and axis drives to run through the contactor(s). That way e-stop kills drive power to moving things. By controlling the contactor(s) with the NoFaultOut signal, motor power cannot be enabled until after the control boots up, and the motor power is disconnected at the start of the control shut down.

You may need more than one contactor. Some people use one for the VFD, and a separate one for the drives. Both are controlled by NoFaultOut. You also want to be sure and switch the incoming power to the drives/VFD,not the outputs. You can destroy your drives by disconnecting the load.

[Eric]

Tom,

Thank you for the clarification! However, I’m not sure if I understood it completely. Are you suggesting to switch power in two places? Just to be clear, let me visualize everything below to see if I’m on the same page here.

Current state:
1. 60V DC motor power and 5V DC logic power -> GR214V drive -> Stepper motor
2. 1 phase 220V AC -> VFD -> 3 phase 220V AC Spindle

What I’m thinking:
1. 60V DC -> Contactor -> GR214V drive -> Stepper Motor
2. VFD Common -> Contactor -> VFD -> 3 phase 220V AC Spindle (Per @cnckeith in viewtopic.php?f=60&t=9869&p=84863&hilit ... tor#p84863, my understanding is that it will stop the spindle in the event of ESTOP)

What I understood from your suggestion:
1. 60V DC (incoming power?) -> Contactor -> GR214V drive -> Contactor -> Stepper motor
2. 1 phase 220V (incoming power?) -> Contactor -> VFD -> Contactor -> 3 phase 220V AC Spindle

Did I understand your point correctly in ^? Also, what am I missing in “What I’m thinking”?

Thanks!