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MAXNC CL10 "qaudrature" and MACH3
« on: March 07, 2013, 03:58:41 PM »

Finally got my MACNC CL10 running under MACH3 using the MAXNC CL mode... yay!

Can anyone explain the theory behind "quadrature" vs. "step and direction"? I find MAX to be useless when it comes to technical documentation (or any documentation for that matter).

The scope of what I'm looking for is this... I want to count STEPS coming out of MACH3 with a separate circuit (like a PIC), however, since both MACH3 and the MAXNC CL are utilizing "quadrature" I'm not familiar with that... would anyone be interested in explaining that, else pointing me to a link that explains it?

I understand the "quadrature" count, but don't have a reference of how it relates to STEP and DIRECTION.

All help is greatly appreciated!
Thank you! 
Re: MAXNC CL10 "qaudrature" and MACH3
« Reply #1 on: March 08, 2013, 07:14:33 PM »
Quadrature means that the windings are driven with a waveform (usually square or sine) that are 90d shifted with relation to each other. Mathematically, it can be stated as a sin and cosine function (sin(x) and cos(x)) :

Say you have 2 pins, A and B as shown in the illustration; the signal on Pin A is the red wave; Pin B blue

So B  would be, say  90 degree shifted ahead of A for clockwise rotation, and 90 degrees behind A for counterclockwise.

Here's vid of mach 3 driving a MAXNC drive on my bench:

Note how the phase (the scope with the "scrambled egg" pattern) displays the phase of the two signals.

another great image:

From EDN:

This is how rotary encoders work (like the volume control on newer radios that spin forever). Not to be confused with resolvers (a whole different beast). We'd use a simple circuit to derive direction and magnitude; as the EDN article states it's now typically done in software using GPIO ports on a micro-controller (I think Arduino even has a sample for this)

Step and directions simply means that one pin is used for the direction (say High for CW, Low for CCW) and the other pin simply "steps"  the amount of rotation. Some controllers allow "micro stepping" which means that the motor will move a fraction of the rated full step rotation.

This is the series I used on my mill, driven by an arduino (it has an allegro driver IC built in )


My mill page:

The vids show it stepping and micro-stepping...
« Last Edit: March 08, 2013, 07:23:25 PM by ajawamnet »
Re: MAXNC CL10 "qaudrature" and MACH3
« Reply #2 on: March 08, 2013, 11:12:04 PM »
Wow, this was excellent info, THANK YOU for taking the time to post this!

I read through the info (except the EDN link didn't work, I think I need to create a login...)

So, it appears that the phase (in reference to A/B) is the direction... is it true then that the *step* is incremented on a rising/falling edge of the wave? When looking at the video  - the o-scope seems to have a constant wave when the motor was NOT running? If steps are either the raising or falling edge... then I would think that A/B would be a constant hi or low while there was no motion (?)

So, still a bit unclear how I would decode *step* info.


Re: MAXNC CL10 "qaudrature" and MACH3
« Reply #3 on: March 09, 2013, 11:01:46 AM »
There's a great read here at this link:

Note in both the unipolar and bipolar links where he states

"In a basic "Wave Drive" clockwise sequence, winding 1 is de-activated and winding 2 activated to advance to
the next phase. The rotor is guided in this manner from one winding to the next, producing a continuous cycle.
Note that if two adjacent windings  are activated, the rotor is attracted mid-way between the two windings.
The following table describes 3 useful stepping sequences and their relative merits.  The polarity of terminals is
indicated with +/-.  After the last step in each sequence the sequence repeats.  Stepping backwards through the
sequence reverses the direction of the motor.  Note that these sequences are identical to those for a Unipolar
Stepper Motor.

As you can see on the top scope (the one that shows the xy plot) the waveforms maintain a constant phase angle during a stop. Please note that the scope is showing the input to the gates of the drive MOSFETs. If you look at the schematic on the yahoo maxnc site - I have a copy of it on my site here:


that otto simply made his software on the PC output a quad signal on two pins to the  PIC microcontrollers. So instead of having to generate the drive signal for the FETS/Darlington transistors (depends on the model MAXNC Controller) from a step and direction signal, he used the MAXNC PC software to generate the quad signal... simplifying the logic required in the maxnc controller/drive. This also allowed him a bit more latitude on being able to alter the drive timing characteristics on the PC side of things.

The old DOS MAXNC disk had a dos program called TIMESET that wrote parameters to a file to control the timing based on the PC's characteristics

This is from an email Art sent me long ago:

"Yes, when you select the CL option, which is quadrature outputs, the pin
settings you use are ignored and set as per factory specs for the CL pins.

Usually, in CL mode the user sets pin 17 as the enable output. Then it is
low until you press reset to enable the controller
at which point it goes high, this suffices to reset the CL.

The Enable pin shoudl work for that.. Also, in CL mode , the Input#1 is
normall used as a hold for position signal to
keep the CL from overruning in speed. I believe pin 10 as below is used. If
pin 10 goes active (Active high) then output stops till the Max determines
its OK for further movement. This makes the CL a semi-closed loop system.
(Hence the CL designation..) Make sure then that pin 10 is set to Input #1
and is set "High active". Setting Pin17 to Enable#1, and setting it "high
Active" as well makes the CL reset when MAch3 does. Also youll notice pin 16
below is the real enable, so you need to set Enable #2 signal to pin 16 and
set it low active" to allow movement when in CL mode.

Here are the MaxCL pinouts..

1............... M3 OUTPUT (LOW=ON, PULSE FOR PWM)
2............... A AXIS (quadrature)
3............... A AXIS (quadrature)
4............... Y AXIS (quadrature)
5............... Y AXIS (quadrature)
6................X AXIS (quadrature)
7............... X AXIS (quadrature)
8............... Z AXIS (quadrature)
9............... Z AXIS (quadrature)
11.............. INACTIVE
13.............. INPUT, G61 SWITCH SENSOR
14.............. M8 OUTPUT (LOW=ON)
15.............. NONE
18.............. ALL SIGNALS GROUND
19 TO 25 ....... NONE

One of the best sites on steppers I've found is at U of Iowa:
Re: MAXNC CL10 "qaudrature" and MACH3
« Reply #4 on: December 11, 2014, 09:06:15 PM »
I am new to MACH3 and am trying to setup my Maxnc10 CL. Every time I turn on the mill, the spindle turns on. What am I doing wrong? Can someone post screenshots of their settings? I should note that I can jog the X, Y, and Z axis fine.

Thanks for your help!
Re: MAXNC CL10 "qaudrature" and MACH3
« Reply #5 on: December 11, 2014, 09:31:04 PM »
I don't remember when I bought my Maxnc, but is was sometime between 1998-2005.