DMM DYN4 Under CNC12 4.18

[Quinn the eskimo]

Marty,
Can you tell me why Dmm specifically says in their manual that the drives are ENABLED by default on power up.
You say that they shouldn’t be enabled upon powered, not till cnc12 says to enable.


And if you freeze frame on the Dmm schematic you are holding in the video you made for the Dmm flying lead cables, the document has notes from Dmm that clearly state to select ENABLE ACTIVE LOW

In fact in that same document you’re holding, a few more lines down, it says specifically to Not invert enable in acorn.
It also says to use 8000 as the gear num and 8000 as the steps per rev in acorn. not the 2000 gear num and 8000 steps/rev that is Commonly being suggested by centroid and Dmm in their own videos. I’ve even seen centroid acorn videos that are instructing us to insert 2000 as gear num and 2000 as steps per rev in acorn. Another contradiction from the same sources.

There’s a lot of conflicting data coming from centroid videos, and Dmm videos and centroid documents and Dmm documents.

The Dmm manual says the only way to eliminate enable on power up is to select Enable Active Low. That’s why Dmm instructed me via phone to select the enable active low button.

Please don’t take my words as being aggressive. I’m just frustrated at the circles I run in. I’ve been trying to get my acorn board to work for over a year now. Warranty is long gone and I’ve never even cut my first file.

I’ll send screen shots of my progress and cabinet shots sometime today.

[martyscncgarage]

Marty,
Can you tell me why Dmm specifically says in their manual that the drives are ENABLED by default on power up.
You say that they shouldn’t be enabled upon powered, not till cnc12 says to enable.


And if you freeze frame on the Dmm schematic you are holding in the video you made for the Dmm flying lead cables, the document has notes from Dmm that clearly state to select ENABLE ACTIVE LOW

In fact in that same document you’re holding, a few more lines down, it says specifically to Not invert enable in acorn.
It also says to use 8000 as the gear num and 8000 as the steps per rev in acorn. not the 2000 gear num and 8000 steps/rev that is Commonly being suggested by centroid and Dmm in their own videos. I’ve even seen centroid acorn videos that are instructing us to insert 2000 as gear num and 2000 as steps per rev in acorn. Another contradiction from the same sources.

There’s a lot of conflicting data coming from centroid videos, and Dmm videos and centroid documents and Dmm documents.

The Dmm manual says the only way to eliminate enable on power up is to select Enable Active Low. That’s why Dmm instructed me via phone to select the enable active low button.

Please don’t take my words as being aggressive. I’m just frustrated at the circles I run in. I’ve been trying to get my acorn board to work for over a year now. Warranty is long gone and I’ve never even cut my first file.

I’ll send screen shots of my progress and cabinet shots sometime today.

The first post I made works. Tested. Others have reported it works.

Early on, DMM did not have Enable Active Low. By default it is not checked. It doesn't matter, you just have to either invert or not invert in the Advaned tap. Do what work best for you.
Marty

[Quinn the eskimo]

So, things have improved a bit. but there is still one or two issues.

I now have cnc12 4.20 software installed. The screw terminal db25 mapping fix for Dyn4 seems to work.

I stripped back everything to just one axis again. The X axis.

Ill post a video here that shows the issues but in case it upload, here's my explanation:

FIRST ISSUE:
When I physically hit the power button on my setup, both the acorn board and my DYN4 drives power up at the same time. As soon as acorn powers up(instantly), its sending a signal to the drives through the DMM flying lead cable. Its causing the connected axis (X) to start crawling along on its own.
If the flying cable is disconnected from the servo drive when i power up, there's no movement.

Meantime, while the x axis is crawling along on its own at startup, I reach over and click cnc12 to start the software. The moment cnc12 finishes booting up, the x axis stops crawling and is ready to be moved by cnc12.

Is it because the DMM drive is set by default to ENABLE upon powering up? And until cnc12 gets booted up to tell the drive "Stand at attention and be ready"?, it will continue to crawl?
If i select "Enable active Low" in the DMM software, and NOT select invert enable x axis in cnc12, this problem does not happen. I wonder if that's why Stephen at DMM had me select the "Enable active low"

Second Issue:
The x axis moves silky smooth in the X+ direction. I've never had it so silent and smooth. But if i jog in the X- direction, the motor makes noise, and as soon as i let go of the jog x- button, the axis begins to crawl back in the X+ direction on its own.

Now, If I add the Z axis to the wizard and setup, the z moves perfectly up and down. The X axis still crawls backwards.
As soon as I add one or two of the Y axis to the wizard setup, the Z axis now makes noise and it will crawl backwards.
Its as if each added axis to the wizard is affecting the other axis. Things are getting exaggerated.
I dont think its a problem with the X axis encoder because the Z axis and Y axis will experience this too.

Also, I've eliminated the possibility its a bad acorn. DMM was nice enough to lend me an acornrev4 board and it does the same things.

Could this be called a runaway? I saw your video on that but your fix was to reverse the polarity of your motors. my motors aren't DC so I cant reverse the polarity by swapping positive and negative like you did.

And speaking of reversing, In the wizard, I had to reverse the direction of the x axis to make it go the right way. It didnt require that before the 4.20 upgrade. The same goes for my Z and Y axis. They too needed to be reversed in order to move the right way. That wasnt necessary prior to upgrading to 4.20

Here are my wizard shots as of this morning:

[Quinn the eskimo]

Heres the video:

[martyscncgarage]

You should have NO motion, until Acorn is on line and the enables set. The enables set when either a given axis is jogged OR you home the machine.
Your motors should not be moving as they are NOT enabled yet. Did you benchtest your drives/motors and Acorn before installing.
Your motor shafts should be FREE until they are enabled.

Further, I would have used an ESTOP contactor on the motor power to the drives. That way motor power is not applied to the 4 drives until CNC12 is on line and not in the fault state. When IN the fault state, the motor power will be removed from the drives. No motor power, no way the motors can turn.
Its the proper and safe way to control motor power.

Do this test. Unhook the X axis DB 25 from Acorn and power everything up. My gut is that the X axis will still do the same thing, as the drives are enabled. Frankly they should DISABLE when Acorn tries to ENABLE the drive.

If your X axis is moving with the DB25 disconnected, I think your motor PID settings in DMMDRV need to be checked. If X does not move when you disconnect the DB25 signal line, something is not wired correctly.

Plain and simple, your motor rotors should NOT be locked when you power up Acorn and the drives. (Until you jog an axis OR home the machine)


Marty

[martyscncgarage]

Please post a screen shot of the DB25 mapping screen.
Is Header or DB25 selected?

[Quinn the eskimo]

Bench testing was certainly done. I had to run miles of new wire so I made sure I had motion before I got really committed.
But I honestly only bench tested one drive, not all four.

I have an e stop, and it works but it doesn’t kill motor power , it’s just triggering input 8 to stop. I’ll change that later like you suggest but I believe that’s not the problem right now.

If I power up the x axis drive with no cable from dyn4 to acorn, the motors do not creep. Therefore it’s not the drive and the Dmm software that causes havoc.

The drive starts to creep if it’s powered up and connected to acorn via the headers.
So I’m guessing the 24volts coming from acorn to the Dmm flying lead Is the root of the problem. It’s voltage that’s present and flowing from acorn into the Dmm drive. Once acorn boots up, and gets a heartbeat things change and the drives stop moving like in my video.

So, when I immediately power up my drives and just my drives with no connection to acorn, the shafts are rigid and not free. They aren’t crawling though, they are just rigid. I understand what you mean when you say the motors should be free upon energizing. They shouldn’t go rigid until an axis is jogged.

However, if I set the x axis to Enable active low, I get the correct result..... power the drive up and I can still push the axis around. I can hear a little hum so I know the motor is on but the shaft is free. When I connect the Dmm flying lead and boot up cnc12, the motor goes rigid after I jog an axis just like it should.

So Enable active low is needed for me to get the shafts free upon powering them up. Dmm says in their own manual that these drives are set to be enabled upon powering up. So that makes sense that I need enable active low turned on so that these drives don’t enable until acorn says so.

What’s got me so puzzled is that you insist that I should not turn on ”enable active low”.

[martyscncgarage]

You are correct.
In my case the drive is enabled by default.
The moment acorn Powers up, it gets disabled because I inverted the Enable, so acorn is holding the enable low until the motor is commanded to move. Then it goes high enabling the drive.

You are doing the opposite. You are telling the DMMDRV software to enable active low.

You should use an Estop contactor controlled by the Acorn relay you have assigned to NoFaultOut
Instill don't think this is going to cure your creep issue. I believe you may have noise in your system.

Did you take all grounds back to one common point where the service earth ground is attached? Including cable drain wires?

[Quinn the eskimo]

I’ve been suspicious of noise via grounding.

This machine was initially a three phase in, three phase out power, but I don’t have 3 phase at my shop so I simply dropped the use of the third leg on my power chord. But one end of that third leg was still connected in the cabinet, and not connected at my plug so I was worried it was acting like an antenna. I disconnected that lead at the cabinet as well but no change.

I will investigate further. I also have extra coiled signal cables inside my cabinet because they were too long from Dmm. I wonder if they might be giving me grief.

Noise from bad servo tuning would be present when I jog x in BOTH directions, no? So this noise created in just one jog direction Could be interference via grounding?

At least it’s a direction to take.

Will keep you posted and thanks for holding my hand in all of this

[martyscncgarage]

Without a scope on the step line, it might be a challenge to find.
Start with making sure you have a good ground and All your grounds go to one.point.

You might consider backing up. Back to bench testing with just Acorn, it's power supply, DYN4 on the bench wired to one motor, say your X axis. See if your motor still jitters or if it's solid. If solid, mount the motor back on the machine and see if it jitters. (Acorn remains on the bench, not in the cabinet) no other input or outputs connected other than an Estop button.)