[kolias]

I'm not there yet but I want to set the switch on the drivers before installing them however the setting for microsteps I’m used to is in 1/2" 1/4" etc format and the manual for DM556T stepper driver gives the microsteps in a format I’m not used to like shown in the attached.

Are any tables available to find the corresponding values or perhaps calculations?

Thanks

[arturod]

The higher the resolution the smoother the motion is, but you tend to lose torque. So you need to play with them while the motors are working under load until you get the optimal performance. Maybe these recommendations may help:
https://cnc4pc.com/faq/article/how-t...stepper-motors

[joeavaerage]

Hi,
there is no magic number.

Microstepping came about because astronomers wanted increased resolution. As it turns out beyond 1/2 stepping that does not work, nice to imagine it does but in practice the best
resolution you can get from a hybrid two phase stepper is 400 steps/revolution. What astronomers did find however that increased microstepping made the motion smoother and that suited their purpose
trying to drive telescopes with the least possible vibration.

The higher the resolution the smoother the motion is, but you tend to lose torque.

That is simplification. Certainly you get smoother motion with microstepping but not actually reduced torque. The issue is the torque between adjacent steps, and that does reduce.

Lets say you have a motor of 1Nm per full step ie 200 step/rev. Most motors will offer the same torque at half steps, so 1Nm @400 step/rev. However at quarter stepping 800 step/rev the torque between any two
steps is halved, ie 0.5Nm. It gets worse at higher microstepping, lets say 16th stepping or 3200 steps/rev the torque between any two adjacent steps is 0.0625Nm.

In this situation you might call for the stepper to rotate one revolution say. A step will be issued but because the torque is so low it will not move until say six or eight steps have been issued and NOW there is sufficient torque
for the motor to move, and move it does.

At about eight micro steps per full step (1600 step/rev) you have got the best increase in resolution that you are going to get and have gotten about as much smoothness gain as you can WITHOUT having to
signal the drives at light speed.

That is my recommendation set the micro stepping anywhere between 1000 step/rev to about 3200 step/rev....and leave it there. You've got about as much benefit as you can without getting into
trouble with ultra high speed signalling.

Then you just have to set the Steps/Unit value to suit the mechanics of the machine.

Craig

[kolias]

The dip switch combo I have only allows me to set the microsteps to 400, 800, 1600, 3200 etc so I will go with either 800 or 400.

If interested, the link to this driver user manual is here
https://www.omc-stepperonline.com/download/DM556T.pdf

Something new to me: the user manual says under paragraph 7.3 "When powered on a DM556T will automatically configure itself with the best settings to match the driven stepper motor for optimal performance, No action needed".

But to make sure I want to do the settings myself. In the attached table which should I select for my motor which is 4.20 Amps/Phase? 4.3A or 4.9A? (the dip switches are now set for 1.8A)

Nicolas

[peteeng]

Hello Kolias - The DM556 is a digital motor driver. You set the microsteps and the max current to suit the application. The driver does not do this. What it does do "automatically" is figure out how to electronically compensate the back emf and the forward voltage to produce smooth motion in the mid range of the motor speed. Motors when spun are generators and this back emf creates weird harmonics with the fwd emf signal. Digital drivers figure this out and adjust various things to produce smooth motion. As the motor really speeds up the back emf becomes dominant and the motor is naturally stopped as the actual driving voltage reduces. Plus there is inductance in the system and an electronics person can explain all of those affects a bit better than me.

When starting to develop a machine I always set the amps low so they will stall easily. As I get confident in the machine I ramp up the amps to the motors until they are max. This way if there is a bump or accident early on the drivers stall and protect the mechanicals... Once at full amps you can damage something in an accident. (how do I know that??? ) Peter

[asuratman]

so I will go with either 800 or 400.

I use DM860H, I also set about 800, I don't know why if going higher it will vibrate. How high usually set the microstepping ?

[kolias]

Thanks for the education Peter, glad I asked the question because I couldn't believe this automatic setting. I'm aware about emf and the problems it can create and I try to keep separate the runs of high volts cables from my limits cables + I use shielded cables and ground their ends to earth. Also I didn't know you can set the Amps lower at the beginning for the reasons you stated but I will now.

Cheers

[kolias]

I use DM860H, I also set about 800, I don't know why if going higher it will vibrate. How high usually set the microstepping ?

The way I do it is by trying various combinations until I hear the motors running smooth. From past experience 400 or 800 is my best choice but I will assume it also depends on the motors and drivers. This is my first time I will use this package from steperonline.

Nicolas

[automationtechinc]

The way I do it is by trying various combinations until I hear the motors running smooth. From past experience 400 or 800 is my best choice but I will assume it also depends on the motors and drivers. This is my first time I will use this package from steperonline.

Nicolas

We use 1600 in our machine setup, It has good performance, You can try it

https://www.automationtechnologiesin...r-motor-driver