The 2DM860H chinese controllers vs the rest?

**Nr1madman** · 21-11-2017

Alrighty!

Might be an idiotic buy after all ;)

So.. current configuration? Should I match peak or RMS settings on the dip switches?

Have 4amp motors (4nm nema23 from cnc4you)
If going for RMS setting for the driver I get 3.42A RMS 4.78A peak.
If going for peak current I get 3.15A peak 2.15A RMS or a slight overshoot at 4.03A peak 2.88A RMS.

For me this seems like really bad options for maximizing my motors.
I know the AM882/EM806 have software options for fine tuning current but this driver does not seem to have this.

So.. what says the experts? :D

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**Ger21** · 21-11-2017

I'd set the drives to 4 amps peak?

**Nr1madman** · 21-11-2017

Originally Posted by Ger21

I'd set the drives to 4 amps peak?

Thanks Ger!
Will try that ;)

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**Neale** · 21-11-2017

I would read the data sheet and set the current to something reasonable. That is science.

Once the machine is running, adjust it so that the motors run at a temperature that is just about as hot as you can comfortably hold, which is around 60C. That is engineering...

Seriously, stepper motors are designed to run hotter than you might expect. More current gives better performance as long as you do not overheat them. Those current readings are really only a guide or a rough starting point, not absolute limits. Remember to set the stationary holding current to half (usually a dip switch setting) which helps keep them a little cooler while not moving.

**Nr1madman** · 21-11-2017

Originally Posted by Neale

I would read the data sheet and set the current to something reasonable. That is science.

Once the machine is running, adjust it so that the motors run at a temperature that is just about as hot as you can comfortably hold, which is around 60C. That is engineering...

Seriously, stepper motors are designed to run hotter than you might expect. More current gives better performance as long as you do not overheat them. Those current readings are really only a guide or a rough starting point, not absolute limits. Remember to set the stationary holding current to half (usually a dip switch setting) which helps keep them a little cooler while not moving.

This is just what I wanted to hear!
Thanks!

I realise why they mark up both peak and RMS current. But it's still misleading when you want a safe maximum ;)

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**Doddy** · 19-04-2020

Real world experience. Tonight I burnt out a stepper (my fault, overdriven on current setting). In doing so it took out the 2DM860H.

Not only on a Sunday, but a Sunday in the middle of a global pandemic.

Got a couple of spare steppers (higher rated) and I can slave the A-Axis controller, but PITA all the same.

**JAZZCNC** · 19-04-2020

Originally Posted by Doddy

Real world experience. Tonight I burnt out a stepper (my fault, overdriven on current setting). In doing so it took out the 2DM860H.

Not only on a Sunday, but a Sunday in the middle of a global pandemic.

Got a couple of spare steppers (higher rated) and I can slave the A-Axis controller, but PITA all the same.

The conspiracy theorists and trumps of this world would say the Chinese did that on purpose..

. . . . Me you just been bloody unlucky mate because it takes a lot to burn out stepper in my experience.

**Doddy** · 19-04-2020

Originally Posted by JAZZCNC

The conspiracy theorists and trumps of this world would say the Chinese did that on purpose..

. . . . Me you just been bloody unlucky mate because it takes a lot to burn out stepper in my experience.

Unlucky?, no, just stupid. I've slaved (via changeover relay) two machines off one set of drivers (with an switching interlock to protect the drivers from disconnection) to save on space and cost. But in doing so I'm driving 40 year old 2.1A steppers at rather higher than they're designed for, so, in honesty, it was waiting to happen. Interestingly the B coil shorted and destroyed the driver - to the point that, from what I can tell, the whole logic is fried - I could understand the power output being destroyed, but to have no LED fault indication was a surprise. But, live and learn - my replacement steppers are rated higher (I'd already replaced the X-axis for more torque) - so all is good. It's just a buggeration to strip the controller down to replace the driver - might wait for a replacement rather than physically moving the A-Axis (depends if I can remember if I tapped the plate that they are mounted to - easy to swap, versus bolted-through in which case have to strip the mount plate out.

**Nr1madman** · 20-04-2020

Hey everyone!
Doddy, I feel your frustration!
Have been thinking about buying spare parts for my router so that if something like this happens I have parts availible "on the shelf".

That beeing said my drivers are still working great.
I usually run my machine 30-50hours per week depending on how many orders I have.
Have noticed resonance on some occasions when I have been running 10-12hours straight and push the feedrates up to get finished.
But that just tells me that my normal speed is optimal 😁

**Doddy** · 20-04-2020

Aha, there's an onboard fuse that's blown... that's the first test (and those two replacement drivers I've ordered.... may eventually come in useful)

EDIT: Premature - that just blows fuses now, guess an output driver is shorted and is now just a fast-fuse-blower.