Counter-rotating motors on common axis

clover

clover
I need to have two counter-rotating motors on my Y axis and for this I am driving them with a Gecko G540, a 4 axis motor driver. The fourth axis input to the G540 will essentially be driven from the MASSO's Y axis output. What is the recommended (or best way) to reverse one of the steppers:
  1. Reverse the windings on the appropriate output of the G540?
  2. Invert the direction signal from the MASSO to the 4th axis input of the G540?
  3. Upgrading the MASSO to a 4 axis unit?

Either option seems feasible although the first seems easiest but the second more elegant - but awkward since it involves adding an i/c with its attendant need for power. The third option is probably the easiest and the most desirable but more expensive.
 

clover

clover
Looking further at the above situation. Is another option to feed one of the Y steppers from the D+ output and the second Y stepper from the D- output of the MASSO's Y axis out?

This would indeed be an elegant solution and forward thinking in the MASSO's design.
 

masso-support

MASSO Support
Staff member
If you want to align your axis during homing and have two separate switches on each side then you will need to use the slaving option on MASSO otherwise you can just wire the drives together as you mentioned as that is also perfectly ok.
 

clover

clover
Sorry about that. They say a picture is worth a thousand words.

Will the wiring arrangement in the attached image work?
 

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masso-support

MASSO Support
Staff member
@clover that is perfect!! please make sure to connect the GND from the gecko to MASSO's power supply -ve or on Pin: G on A or B axis connector.
 

clover

clover
Thank you MASSO. Slightly refined drawing may be helpful to others with hobby CNC routers that require counter-rotating Y Axis steppers.
 

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clover

clover
Thanks MASSO. It's a Mac application called Eazydraw. I have been using it for many years through a number of iterations. When they release a new version with more bells and whistles they retain the older versions but sell them at lower price. Currently on the Mac App store in Oz the various versions are available from: Ver 4 $1.49, Ver 5, $7.99, V6 $22.99 Ver 7 $54.99 and Ver 8 $149.99. There is also a free version that does most things many people would need. The drawing above was done on Ver 7 although I think most of the lesser versions would also be able to produce similar work.

Almost forgot, Eazydraw is a Vector drawing package and will import and export many image formats. I produce most of my CAD work on it exporting EPS to Vectric Vcarve for CAM.
 

flytyree

FlyTyree
The graphic above was superb. However, the only way my system would work is by connecting ALL "-S1's" to the G540 grounds; i.e., pins 18 - 25.
 

flytyree

FlyTyree
I need more help with the wiring of the G540. It is not clear to me how the diagram on page 178 of MASSO documentation is the same as shown in the diagram in this section. I have tried both wiring diagrams with limited success. The first issue I ran into for both diagrams was the screen was showing movement on all three axis's but no movement from the motors. I contacted Gecko and talked with Marcus Freimanis and he stated that the S1's had to be connected to one of the pins on the DB25 18 - 25, I did this and the motors were then operating. But, I cannot HOME the system. Z axis starts the homing sequence correctly and then X and Y motors vibrate but do not move.

Ignoring the homing issue I have been able to cut some parts with reasonable accuracy. I don't think I will ever get the accuracy I am looking for until I replace the Z axis system. Any suggestions.

Thanks in advance for your review.

Clifford
 

clover

clover
Sorry to hear that you are still having troubles Clifford @flytyree. My diagram posted above (dated 14 August) and the Masso Manual's diagram (image below) are the same with two exceptions.
  1. My diagram is for counter-rotating Y axis steppers, whereas the Masso diagram shows Pins 8 & 9 of the G540's DB25 connector wired to a 4 axis Masso.
  2. My diagram shows the power supply common (ve-) wired to the G540 as described by @masso-support in the quote below. The diagram in the Masso Manual does not show this ground connection - it is assumed. -EDIT- My apologies it is shown, see the green line connected to pin 25 of the D25 connector

please make sure to connect the GND from the gecko to MASSO's power supply -ve or on Pin: G on A or B axis connector.

I have difficulty in understanding this statement:
he stated that the S1's had to be connected to one of the pins on the DB25 18 - 25

What pins are S1's? Are you referring to - the S+ or S- pins on the Masso? If you are connecting the S- pins to the DB25s 18-25 pins it may work but you are risking damage to your Masso (especially if you are powering the Masso and the G540 from the same power supply).

Again, if it does work with these S- pins connected and doesn't work without them there is a good chance you do not have the ve- connection as described in point 2 above. If the gentleman from Gecko with whom you spoke recommended connecting either S+ or S- to the DB25's Pins 18-25 he is unfamiliar with Masso and the advice should be ignored.
But, I cannot HOME the system. Z axis starts the homing sequence correctly and then X and Y motors vibrate but do not move.

Let's sort out the connection problem first. Hope this is of some help. Cheers, Patrick
 

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flytyree

FlyTyree
Patrick, THANK YOU for your response.
  1. I am working with counter-rotating motors
  2. The power supply to the MASSO and to the G540 are separate.
  3. I was referring to the -S pins

For my clarification; -ve from the power supply for the MASSO ties to the GND on the DB25 AND TO the G pin on the A axis. Is this correct?

At this point before I power on I will disconnect the -S from the DB25 before any power is reapplied.

Thank you again.
 

breezy

Arie
Staff member
Quote from FlyTyree on October 19, 2018, 11:04 pm

Patrick, THANK YOU for your response.
  1. I am working with counter-rotating motors
  2. The power supply to the MASSO and to the G540 are separate.
  3. I was referring to the -S pins

For my clarification; -ve from the power supply for the MASSO ties to the GND on the DB25 AND TO the G pin on the A axis. Is this correct?

At this point before I power on I will disconnect the -S from the DB25 before any power is reapplied.

Thank you again.

You could also purchase a Masso to Gecko Parallel from 3DTek and have it work without the headache.

MassoGeckoAdaptor1



To get counter rotation on the motors you just reverse two wires on one of the motors.

That is how it is installed on our Heavy Mill.

Regards,

Arie.

For the Bicton Men's Shed.
 

masso-support

MASSO Support
Staff member
Quote from FlyTyree on October 19, 2018, 11:04 pm

Patrick, THANK YOU for your response.
  1. I am working with counter-rotating motors
  2. The power supply to the MASSO and to the G540 are separate.
  3. I was referring to the -S pins

For my clarification; -ve from the power supply for the MASSO ties to the GND on the DB25 AND TO the G pin on the A axis. Is this correct?

At this point before I power on I will disconnect the -S from the DB25 before any power is reapplied.

Thank you again.

@flytyree you can simply swap th 4 wires going to the stepper motor and it will change the motor direction.
 

breezy

Arie
Staff member
Quote from MASSO - Support on October 20, 2018, 3:28 am

@flytyree you can simply swap th 4 wires going to the stepper motor and it will change the motor direction.

Swapping 4 wires will not reverse the motor direction because it results in current reversal in both sets of coils and you still will rotate the same direction. You swap 2 wires to reverse the current flow in one set of coils and this reverses the motor.

Regards,

Arie.
 
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