no step count or enable signals to stepper motor

[Clive598]

hello there I'm just wondering if anybody can shed some light on an issue I am having with the output to the stepper driver.

I have loaded up the software V 1.1.02 onto the launch board and I have the boosted board plug in the top when I spin the encoder the RPM display works fine.

the problem I'm having the is there is no change of signal on the step output or on the enable output. I do though get a output on the direction pin depending on which way I turn the encoder.

I have tried changing the #define INVERT_STEP_PIN true but all this does is change the output value to low.

if I tried to invert or comment out the // #define INVERT_ENABLE_PIN true it stays at high potential whatever I do in the configuration h. file

I have put an oscilloscope on both outputs and not seen any change signal. Also I have connected three LEDs with 4.7 K resistors to the 5v supply from the boosted board to each of the outputs. the only LED that changes when the encoder turns is direction.

I would really appreciate if anybody can help me with this problem I'm having maybe it's something silly I have done or overlook. also many thanks to John for sharing this awesome project.

[JonWoellhaf]

Hi, Clive598.

Hope I can help.

Please verify the position of S3 and S4 on the TI board. They're under the Boost board.

Both S3 switches need to be positioned away from U9 -- toward the dot on the switch housing. S4 also needs to be positioned away from U9 -- toward the dot on its switch housing.

[JonWoellhaf]

Please try this:

1) Disconnect the resistors and LEDs.

2) Put one of the resistors from + to STP- on the servo driver connector.

3) Put your scope on the STP- lead, spin the encoder, and see what you get.

[Clive598]

HI Jon

Thank you for responding to my request for help.

I have checked the switches and they are as you say.

I have disconnected the LEDs and placed a 4.7 K resistor between 5V+ and STP- when I rotate the encoder I get no signal On the scope.

[JonWoellhaf]

OK. This is like déjà vu all over again. :)

Please put your probe on pin P00 of J8 on the back of the TI board, spin the encoder, and see what you get.

You should see a 5 us wide positive pulse at about 3.2 volts when you spin the encoder.

[Clive598]

HI Jon

I found the pulse at the pin 5 µs 3.3v

I also read pro at the boosted board and found the signal 5 V

[JonWoellhaf]

OK!

I think there's a typo in your last message. Am I correct that you saw the pulse on the STP- terminal on the servo driver connector?

If so, its polarity is incorrect, so in Configuration.h change line 71 to be

71 // #define INVERT_STEP_PIN true

Then check the STP- signal. It should be a 5 us wide negative going pulse at about 5 volts.

[Clive598]

HI Jon

I changed the configuration file as you said copy below

// Steps and microsteps

define STEPPER_MICROSTEPS 8

define STEPPER_RESOLUTION 200

// Step, direction and enable pins are normally active-high // #define INVERT_STEP_PIN true // #define INVERT_DIRECTION_PIN true // #define INVERT_ENABLE_PIN true // #define INVERT_ALARM_PIN true

// Enable servo alarm feedback // #define USE_ALARM_PIN

this is the signal I get now

this is a stepper motor driver I have tried to interface to

[JonWoellhaf]

OK. Let me take a look at that driver.

Meanwhile, do you have heat shrink tubing? I am concerned the wires from A+, A-, B+ and B- to your motor connector are very close to shorting. Please cover the connector contacts with heat shrink tubing before applying servo power again.

[Clive598]

HI Jon Okay I will tidy up loose cables. I also have datasheet on stepper driver

Stepper Motor Driver Controller B6600.pdf

[JonWoellhaf]

Please try this:

1) Remove all the wires from J2 on the Boost board and the Signal connector on the servo driver.

2) Connect + on J2 to PUL+ on the servo driver.

3) Connect STP- on J2 to PUL- on the servo driver.

What servo motor are you using?

The TB6600 driver pdf is a bit sparse! :)

I am assuming your servo driver behaves similarly to others I've read about where leaving the EN input open defaults to Enabled. We shall soon see if that's correct. :)

[Clive598]

HI Jon

thank you very much for your time and patience with me success all working the servo leads going from driver to the motor were crossed I have followed the datasheet but I should have also checked with the meter the coils of the motor as well.

after realising this mistake I made I thought I'd just quickly reverse the enable pin to see if it would work. and it did.

The stepper motor I'm using is a Nema 17 but the biggest one I could find. the lane is quite a small one and I would only be using it for light thread cutting.

if there wasn't enough power I was thinking about putting two of those stepper motors on the lead screw. My idea is to try and build everything into the lane itself there is room in a box that the lead screw passes through where both the motor could be.

I will put the first motor on temporarily to see if it has enough power.

once again I thank you very much I really was at a loss and I couldn't see a way forward to get this working.

when I get it all together I will post pictures of this conversion on the Waco

Kind regards, Clive

Nema 17 stepper motor.pdf

[JonWoellhaf]

Excellent!

Thanks for another fun puzzle to solve. (You made this one too easy, though.)

Jan (Yan)