NI Softmotion Module to control 4 stepper motor for 3D printer

[eltico]

Kashish,

The C series modules can only drive one axis per module so you'll need 4 of them. I found something it might be better, check the link below:

https://www.ni.com/en/support/downloads/tools-network/download.sisu-1004-c-series-module-software.ht...

You could also check the link below for drives compatible with SoftMotion and see if any of those vendors have drives for multiple axes, that might be as expensive as just buying 4 C series modules.

Regards,

PedroR

https://www.ni.com/en/support/documentation/supplemental/15/using-ethercat-motion-drives-with-ni-rea...

[Kashish]

Dear Pedro,

I looked at the manual of SISU Module and I found out that it has 2 DI/O pins (i.e. step and direction) instead of 4 DI/O pins (i.e. A+,A-,B+,B-). So, I was wondering if it will it able to control bipolar stepper motors using PWM signals?

Regards,

Kashish Dhal

[eltico]

Kashish,

I am not sure about that to be honest, as far as I know, you'll need the 4 signals but they are basically opposite so you can acquire an inverter to feed the other inputs of the drive. This is just a guessing though, it may differ depending on the hardware you are using. 

If you'd like to get help about using that toolkit, contact the manufacturer. They should have more accurate information about it. 

Regards,

PedroR

[Kashish]

Dear Pedro,

Thank you for replying.

Even I got confused, when I looked at Stepper Interface 9512 & Stepper Interface 9401 examples in the example folder. Both of them have step and direction only (no a+,a-,b+,b-). So, its not SISU, even NI is using the same concept.

As far as I know, to control a stepper motor, we need atleast 4 signals, which are the permutations of 0 & 1 over 4 digits. And all of them can be high or low, (like 1000, 1010, 1110, etc). If we use an inverter then it means when one signal is high all other three signals has to be low (1000). When one signal is low, other 3 will be high (0111). So, how will it give all permutations? And there has to be some role of direction pin as well. I may be wrong over this. But it didn't get the concept of using inverter.

Referring to Stepper Interface (9401) example, they have used DIO module. Basically for my project, I will need 4 pins for 4 phases(a+,a-,b+,b-) and 3 pins for limits and home positioning. So, I will be needing 7 pins per axis, so if I buy one DIO module with 32 bidirectional channels then possibly I can start. Or as you recommended I can use DIO of my-rio by connecting it to C-Rio. But the example for 9401 is again based on Step and Direction pins. So I think, we need a logic or controller to convert those signals into 4 phases. Also, those signals for 4 phases will not be of same voltage as provided by module. Motor will need high voltage and current. So, I think we are missing either a controller or something else. Can you please look into it?

Thanks,

Kashish Dhal

[Karl-G · Accepted solution]

It looks like there is a fundamental misconception about stepper control here. The four phases of a stepper motor (the A+, A-, B+, B- being discussed), are to be supplied current by a drive. The 9512, 9401, and SISU-1004 modules are designed to interface to a drive using step and direction pulse trains. Their digital outputs are not designed to supply enough current to power a motor.

There are many options for stepper drives. The NI 9503 module is a C Series drive for stepper motors consuming less than 75W of power, and the SMD-76xx series of stepper drives are rack-mount compatible external drives. We also support many different drives via EtherCAT, at least Copley and Elmo both have drives that can be used with third-party stepper motors.

https://www.ni.com/en/support/documentation/supplemental/15/using-ethercat-motion-drives-with-ni-rea...