H-bridge dc motor on 1XD

verminsup

I have been working on a Stratasys conversion for work. They want to use all the original hardware, this includes the Dc servo motors for the extruder. I have been using servo drives together with 1XD boards but now one of the drives is broken and they want me to use a H-bridge for the extruder. I know this isn't a good idea but it's not up to me.

I'm using the L298N

The pins for the stepper driver and how I have them configured right now on the L298N
D0_STEP(-)
D0_STEP(+)
D0_DIR(-) pin 8
D0_DIR(+) pin 9
D0_EN(-) EN-
D0_EN(+)

On the L298N I can supply a Pwm signal for speed control on pin 7 and then set the direction with the standard dir pins. I was wondering if the other pins from the 1XD drive give out a pwm signal (and be used for an extruder)? Or is there another way of configuring this like using the fan pwm signal. I was told that the step pins have a pwm signal but I can't set the speed with those.

This is the part of the config that matters for the drive
M569 P0 S1 R0 T4000;

alankilian

@verminsup

I'm not quite sure what you are trying to do, so I'll type what I think I read fro your posting:

You are trying to run a Stratasys extruder which has a DC motor and encoder on it.
You are going to ignore the encoder and run the extruder using PWM through an H-Bridge driver.

Questions:

How are you going to have the Duet control the amount of extrusion?
How are you going to get yourself out of this situation of having other people make design decisions you have to try to implement? (That's just a joke. I feel your pain man.)

I'm probably misunderstanding something (I hope anyway.) If not, we can get you squirting out plastic at a nonconstant rate, but I'm not sure we can get you to something that's going to make parts.

o_lampe

@verminsup
I've experiemnted with DC-encoder motors to act like steppers and controlled them via step, dir, enable. From my experience you can't do that without reading the encoder signals.

BTW: I use the TB6612FNG driver which has way better performance than the dinosaur L298.

verminsup

@o_lampe
I have found this driver.

But I'm still not sure how I'm going to let the duet extrude a specific amount.

I'll check that driver

verminsup

@alankilian
I'm not sure how I can give a specific extrusion amount
By having someone stubborn above me

verminsup

Also I got it working just fine but now all of a sudden both drives have stopped working.
Got some very nice prints out of it

alankilian

@verminsup Yeah!

That Rhinomc.com driver looks perfect for your job although I can't find it on their page, so maybe they don't make it anymore.

It's great you've gotten your machine running again.