Posts made by mattling9

One last question, Is there a way to bypass the homing?

i understand motors will not move until homed, so can i just leave the homex.g files blank or does there have to be some sort of movement to make it a valid home?

@dc42 said in Changing G-Code To Control 6 Stepper Motors:

M584 X0 Y1 Z2 U3 V4 W5 E10

Adding the E10 does make a lot of sense! I didn't think it would be that easy to get it working!

Thanks so much for your help

@dc42 Thanks so much for your help! this is exactly what i need!

M584 U0 V1 W2 X3 Y4 Z5 would do the trick??

I am using a DuetWifi and Duet 2X Board to connect 6 stepper motors for a robotic arm project. So far i can control the X, Y and Z axis as usual but i want to be able to control the other 3 stepper motors in the same way without treating them as extruders.

Can someone please explain how i am able to do this?

Here is my current Config.g

; generated by RepRapFirmware Configuration Tool v2 on Thu Feb 21 2019 16:57:55 GMT+0000 (Greenwich Mean Time)

; General preferences
G90 ; Send absolute coordinates...
M83 ; ...but relative extruder moves

; Network
M550 P"RoboticArm Firmware 1.1" ; Set machine name
M551 P"<my password name>." ; Set password
M552 S1 ; Enable network
M587 S"BTHub3-F8KX" P"<my password name>" ; Configure access point. You can delete this line once connected
M586 P0 S1 ; Enable HTTP
M586 P1 S0 ; Disable FTP
M586 P2 S0 ; Disable Telnet

; Drives
M569 P0 S1 ; Drive 0 goes forwards
M569 P1 S1 ; Drive 1 goes forwards
M569 P2 S1 ; Drive 2 goes forwards
M350 X16 Y16 Z16 I0 ; Configure microstepping without interpolation
M92 X200.00 Y200.00 Z200.00 ; Set steps per mm
M566 X50.00 Y50.00 Z50.00 ; Set maximum instantaneous speed changes (mm/min)
M203 X1000.00 Y1000.00 Z1000.00 ; Set maximum speeds (mm/min)
M201 X10.00 Y10.00 Z10.00 ; Set accelerations (mm/s^2)
M906 X2000.00 Y2000.00 Z2000.00 I30 ; Set motor currents (mA) and motor idle factor in per cent
M84 S30 ; Set idle timeout

; Axis Limits
M208 X-300 Y-300 Z-300 S1 ; Set axis minima
M208 X300 Y300 Z300 S0 ; Set axis maxima

; Endstops
M574 X1 Y1 Z1 S1 ; Set active high endstops

; Z-Probe
M558 P5 H5 F120 T6000 ; Set Z probe type to switch and the dive height + speeds
G31 P500 X0 Y0 Z2.5 ; Set Z probe trigger value, offset and trigger height
M557 X-285:85 Y-285:10 S20 ; Define mesh grid

; Heaters
M140 H-1 ; Disable heated bed

; Fans

; Tools

; Automatic saving after power loss is not enabled

; Custom settings are not configured

@bearer these are the motors i am using:

NEMA 17: https://www.oyostepper.com/goods-50-Nema-17-Stepper-Motor-Bipolar-59Ncm-84ozin-2A-42x48mm-4-Wires-w-1m-Cable-Connector.html

NEMA 23: https://www.oyostepper.com/goods-77-Nema-23-Stepper-Motor-Bipolar-18-deg-19Nm-269ozin-28A-32V-57x57x76mm-4-Wires.html

The torque curve for each can be found on the website. This is the torque curved used in my calculations. For these two motors, are my calculations correct in saying the NEMA 17 with a 10:1 gearbox will produce more torque than the NEMA 23 with a 3.33:1 gearbox if the gearbox output is to be 60RPM as seen on the graph???

@dc42 Thanks for your help!!

That does make sense to me but i am still a bit of an amateur in regards to this topic.

The NEMA17 Inductance is 3.0mH ± 20%(1KHz) and the NEMA 23 inductance is 5.4mH ± 20%(1KHz).

Correct me if i am wrong, so this means the Pull-Out data from the manufacturer, for the NEMA17 constant current varying voltage was used and for the NEMA 23, constant voltage varying current was used?

Thanks again for you support!

Does that mean that the NEMA23 will actually output more torque than the NEMA17?

Hi All,

I apologise the is has nothing to do with the Duet but i know a lot of you guys from here are very smart and know a lot on the topic of stepper motors.

I am conducting a study on NEMA 17 and NEMA 23 stepper motors and trying to find the highest torque i can get from each motor when attaching them to a gearbox. I have already selected a specific NEMA 17 and NEMA 23 and i am using pull out torque data from the manufacturer of the selected motors.

The blue and orange lines above show the pull out torque of the NEMA 17 and NEMA 23 respectively. In essence, the pull out torque is the maximum torque the motor can output whilst rotating at certain speed (RPM).
This data is fine and the results are as expected, at low RPMs, the NEMA 23 has a much higher torque than the NEMA 17, whereas at higher RPMS the NEMA 17 can output higher torque than the NEMA 23.

For the project i will be using a gearbox on the motors, therefore i wanted to find the gear ratio that yields the highest output torque of the gearbox, given a desired output RPM of the gearbox. For this example i have said the desired output speed of the gearbox is 60RPM. For the range of different RPMs of each motor, i calculated the gear ratio required for the stepper motor rotating at X RPM to create an output speed of the gearbox of 60 RPM. This calculated gear ratio can then be multiplied by the pull out torque of the motor at X RPM in order to find the output torque of the gearbox.

Here's the part i need help with:

Looking at maximum output torque of each motor with a gearbox (The green and red lines), it can be seen that the NEMA17 outputs the most torque at 600 RPM, which means a 10:1 gear ratio is used (600RPM of motor / 60RPM of gearbox output), whilst the NEMA23 outputs the most torque at 200RPM with a gear ratio of 3.3:1 (200RPM of motor / 60RPM of gearbox output).

This seems odd to me as the results show that with a gearbox, a NEMA 17 is actually stronger than a NEMA 23. This seems odd, simply due to the shear size and mass of the NEMA 23 i would expect it to be stronger. However looking at how quickly the torque of the NEMA 23 drops off at higher RPMs, it seems this could be true.

Can a NEMA 17 with a 10:1 Gearbox REALLY output more torque than a NEMA 23 with a 3:1 Gearbox if the output speed of the gearbox is fixed at 60RPM???

@dragonn

Having connected all motors it seems to be working now Seeing as i will be using 6 motors for movement, do i just set X, Y and Z for 3 of them and E0, E1 and E2 for the other 3?

@dragonn

For the Gear Ratios, do i simply multiply the Desired Steps Per mm (Say 80) by the gear ratio (25:1) to get a final Step Per mm of (80 * 25 = 2000)?

Here is my Homeall.g:

; homeall.g
; called to home all axes
;
; generated by RepRapFirmware Configuration Tool v2 on Thu Feb 21 2019 16:57:55 GMT+0000 (Greenwich Mean Time)
G91 ; relative positioning
G1 Z5 F6000 S2 ; lift Z relative to current position
G1 S1 X-405 Y-605 F1800 ; move quickly to X and Y axis endstops and stop there (first pass)
G1 X5 Y5 F6000 ; go back a few mm
G1 S1 X-405 Y-605 F360 ; move slowly to X and Y axis endstops once more (second pass)
G1 S1 Z-605 F1800 ; move Z down stopping at the endstop
G90 ; absolute positioning
G92 Z-300 ; set Z to axis minimum (you may want to adjust this)

; Uncomment the following lines to lift Z after probing
;G91 ; relative positioning
;G1 S2 Z5 F100 ; lift Z relative to current position
;G90 ; absolute positioning

Hi All,

I have a DuetWifi and Duet2 Board in hopes to control a 3D Printed 6 axis robotic arm. I am using Nema 17 Steppers and 1x Nema 23 for the shoulder joint.

I have had a go at modifying the RepRap firmware but i am getting insufficient axis homing messages and due to having 25:1 and 50:1 gear ratios at the joints, i'v had to make the bed size very very large for the motors to provide adequate rotation. This seems like a quick workaround to get the motors turning, but i want something that works better than this solution.

1) Can you run other firmware the DuetWifi and if so, which?

2) Can the gear ratios somehow be put into the firmware?