Serial stepper driver

Hello motorheads :D

I have taken a bipolar stepper motor out of an epson printer and I would like to control it with arduino. In the printer the motor is driven by a serial driver (LB1946 here the specs).

I would like to use its original driver, but I am not sure where to start. I have found many instructions on drivers for bipolar steppers, but in most cases they refer to a DIR and STEP logical inputs, which this driver does not have. Instead, it has a CLK, SET and DATA logical inputs (which I believe are used to send serial data to the driver serial/parallel converter) and a ST input (which I believe is used for sending pulses). However, I have difficulties applying what I have read in this forum about stepper drivers or about serial communication. Would anyone be so kind to help me figure out things?

Of course I have given what I think is the most relevant information, but please ask me if you need to know more in order to help me. Thank you!

I can't immediately see any information in that link about the data that it expects to receive - for instance what command would you send to make it move 1 step clockwise?

If you don't have the experience to figure out that stepper driver it might make more sense to use one of the common ones. Do you know how much current (amps) your motor requires? If not, perhaps you can measure the coil resistance (ohms).

...R

Hi Robin

thank you for your answer and yes - I can't see any information about the data I should send to make it move 1 step forward (or backwards).. that's exactly what left me confused.

Anyhow from the printers' service manual I read the following: the motor is a 4 wires bipolar drive/constant current drive motor, the drive voltage is 42V (voltage applied to the driver) the winding resistance is 7 ohm per phase and the inductance is 10.0 mH (1kH, 1Vrms).

Do you get anything useful out of it? You suggested I should go for a common driver - could you point me at one that would work with this motor (hopefully nothing too expensive...)?

Again thank you very much

Paolo

7 ohms and 42 volts suggests 6 amps. I suspect that is far too high, maybe by a factor of 3, 6 or 10. You really need to know the voltage of current at the motor rather than at the driver.

How big is the motor physically?

If it was my motor I would try it with a Pololu DRV8825 driver and I would set the current limit at 1 amp and see (over a short period of time) how hot the motor gets. I would try it with a 12v supply simply because it is convenient for me. I suggest the DRV8825 because it can handle more current than an A4988 in case you motor can run at 2 amps.

All of this is guesswork with no guarantees

…R
stepper motor basics

Hi.

I got some of them from old epson printer too, but never tried to use them. With this post I started to dig over google, so far the best I got is this:

http://tangopardo.com.ar/2cf7/2011/03/21/controlling-an-lb1946-via-usb-with-an-avr

Sincerely I did not test or saw the code provided. Could help.. don't know.

Robin2:
7 ohms and 42 volts suggests 6 amps. I suspect that is far too high, maybe by a factor of 3, 6 or 10. You really need to know the voltage of current at the motor rather than at the driver.

How big is the motor physically?

If it was my motor I would try it with a Pololu DRV8825 driver and I would set the current limit at 1 amp and see (over a short period of time) how hot the motor gets. I would try it with a 12v supply simply because it is convenient for me. I suggest the DRV8825 because it can handle more current than an A4988 in case you motor can run at 2 amps.

All of this is guesswork with no guarantees

…R
stepper motor basics

Hi

This popolu should be fine as I could understood over the LB1946 PDF driver specs:

Specifications
Absolute Maximum Ratings
at Ta = 25 °C
Parameter Symbol Conditions Ratings Unit
Motor supply voltage VBB 50 V
Peak output current I O PEAK tw ≤20 μ s 1.75 A
Maximum continuous output current I O max 1.5 A

Correct me if I´m wrong, the epson stepper attached to this driver is working fine at max 1.75 amp driver specs.

I got some of them from old epson printer too, but never tried to use them. With this post I started to dig over google, so far the best I got is this:

http://tangopardo.com.ar/2cf7/2011/03/21/controlling-an-lb1946-via-usb-with-an-avr

thanks - I had also bumped into that bud did not know what to make out of it. It seems quite complex for someone with no experience and the usb implementation makes things even more complicated. I followed Robins suggestion and bought a more common driver. I found the A4988 at a local dealer (it seems that with a dissipator it can handle 2A as well?) and will play a round with that ...

thank you both! Paolo