Need Help!- A3952SW question

[Drools]

I have salvaged 2 of these boards. Each board has 2 x A3952SW and the extra components to drive a bipolar stepper. I have done my best to reverse engineer the wires that were going to the main PCB however I'm not sure if this can be driven from a normal step/direction command interface. I hope someone here can set me straight.
Thanks for the help.

6 wires coming from Main PCB are:
Black---- GND: ground plane on PCB pin 1 on both A3952
Yellow--- Ref: pin 5 on both A3952
Grey----- PhaseB_SideB: pin 8 on SideB A3952
Blue----- PhaseA_SideA: pin 8 on SideA A3952
Red----- +12 or some voltage: pin 3 on both A3952
Brown--- +5 pin: 7 on both A3952

[Iron-Man]

This is from page 9 of A3952 datasheet, Pinout ,application circuits FULL-BRIDGE PWM MOTOR DRIVER ,
"The MODE terminal can be used to optimize the
performance of the device in microstepping/sinusoidal
stepper motor drive applications."

Not sure if this helps, but it shows two A3952 being used to drive a bi-polar stepper motor.

Hope this helps,

Iron-Man

[Drools]

Thanks for the reply Irom-Man.
I have that datasheet and have read most of it but what I do not understand is, what signal do I apply to pin 8 to get the motor turning. Do I have to supply a PWM signal on pin 8?

[Iron-Man]

Originally Posted by Drools Thanks for the reply Irom-Man. I have that datasheet and have read most of it but what I do not understand is, what signal do I apply to pin 8 to get the motor turning. Do I have to supply a PWM signal on pin 8?

I am looking at this a little closer. From what I can tell by looking at the truth table, if you look at "the Forward - Reverse, Slow-Decay Mode" for example. You will notice that if you change the PHASE, from H to L, you can reverse the direction. This mode appears to be recommended for stepper motors. With some simple logic, this could work as a "direction input". Will have to look at the PWM function for the "step input". This chip may work if you can get past the "SYNCHRONOUS FIXED-FREQUENCY PWM".

Iron-Man

[Drools]

If this helps, it seems the mode and enable pins are wired to ground so they are always low.

[Iron-Man]

Originally Posted by Drools If this helps, it seems the mode and enable pins are wired to ground so they are always low.

Yes, you would want to set the "enable" and "mode" pins to low. See page 7, Figure 3 — Synchronous Fixed-Frequency Control Circuit. I believe that this is the key. You could try the "RC" pin as the "step" pin and see what happens.
Figure 3 shows a "step" input but with a fixed frequency, you want mach 3 etc, to control this frequency.
It is possible that the circuit board you have was made to drive a stepper motor.

Hope this helps,


Iron-Man

[Drools]

I'm sorry I-M I should have mentioned there was a bipolar 5ohm per phase, 7.5 deg per step bipolar stepper hanging off the larger white connector in the pics. I was looking at using one of these with an atmega48 uC and nema17 (1.8) bipolar to handle the traverse function on a pickup winder I want to make. I have an 18VDC gear-head motor for the bobbin. I want to have 3 settings low/med/high. The gear-head motor runs fine at 5vdc and I cannot stop the shaft with my fingers at 5vdc. I was thinking lo = 6vdc, med = 12vdc and hi = 18vdc. The nema17 handling the traverse will have to speedup or slow down depending on the setting of the gear-head motor.
More people might be interested in the project. Maybe I should just look at an m48 and an uln2003 to control the stepper and save this hardware for something more complex.

[Iron-Man]

Originally Posted by Drools I'm sorry I-M I should have mentioned there was a bipolar 5ohm per phase, 7.5 deg per step bipolar stepper hanging off the larger white connector in the pics. I was looking at using one of these with an atmega48 uC and nema17 (1.8) bipolar to handle the traverse function on a pickup winder I want to make. I have an 18VDC gear-head motor for the bobbin. I want to have 3 settings low/med/high. The gear-head motor runs fine at 5vdc and I cannot stop the shaft with my fingers at 5vdc. I was thinking lo = 6vdc, med = 12vdc and hi = 18vdc. The nema17 handling the traverse will have to speedup or slow down depending on the setting of the gear-head motor. More people might be interested in the project. Maybe I should just look at an m48 and an uln2003 to control the stepper and save this hardware for something more complex.

Drools

Thanks for the additional information. I bet that this board was designed to run in a fixed frequency mode. Sounds like a good idea to save hardware for later. Were you able to get the stepper motor to run at all?

Iron-Man

[Drools]

I have not even tried to hookup power to the board. Another thing, I took the heatsink off the board to get a better look at the pins and I yes the enable and mode pins are wired to gnd.
So in order to use this board I would have to input a fixed frq signal on the pin 8?
What would this type of board be good for? The stepper that it was driving is a propritary design but it is about the size of a nema23.

[Iron-Man]

Originally Posted by Drools I have not even tried to hookup power to the board. Another thing, I took the heatsink off the board to get a better look at the pins and I yes the enable and mode pins are wired to gnd. So in order to use this board I would have to input a fixed frq signal on the pin 8? What would this type of board be good for? The stepper that it was driving is a propritary design but it is about the size of a nema23.

From the table, pin 8 is active low, i.e. a low will enable the chip. Try the RC pin. The RC pin is pin 6 on the A3952SW. See if you can trace pin 6. Being a propriety board, it is hard to tell. It could have been used in a timer function.

Iron-Man