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Rotary motion fails on flip

I'm trying to set up MX3 to use the second axis as a pan control. I'm using cont rather than sms and I want the pan motor to reverse when the sled on the Stage Zero reverses via switches connected to Aux A.

I want the Stage Zero to move back and forth and change directions on both pan and sled direction. There is no connection to the camera as I'm using it for straight video recording, not time lapse.

I have programmed the rotation rate on the Axis 2 (pan) and everything works fine in sync with Axis 1 (sled motor). It dollies and pans as expected, but after a trip or two, the pan motor no longer functions. I can go in and move the pan motor manually with the manual controls on the MX3, but I can not get the motor to move in any direction after the first trip or two in programmed run mode.

The MX3 manual barely touches on anything helpful regarding setting up rotary panning of motors and after hours of trial and error I finally got it to work-- at least to a degree, then Aux 2 motor suddenly quit working after a trip or two. If I wipe everything and set it up again after reset, it works for a while then stops again.

Is this a software bug in the MX3 or is there something needed to be set to prevent this issue?

I have upgraded firmware and there were no change in results of the issue (updated 1/12/15)

MX3 configuration:
Cont mode
Axis 1 - motor for moving Stage Zero sled - Rotary off
Axis 2 - motor for panning camera - Rotary on
Aux A - Set to flip motors



Chuck Butler

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Hello Chuck,

Hmm, some quick testing here and I can't reproduce your problem.. My first inclination is your pan motor is having power connectivity issues, you might try a gentle 'pinch' of the motor's male connector, occasionally these barrel connectors can be a little out of spec and can loose connectivity in the center pin hole. By ever so slightly pinching the connector this will make it 'grip' the center pole on the MX3 side and make sure it doesn't loose connection..

Is there something in particular you're having a hard time understanding about setting up the rotary motor? Basically the only setting you need to set is the 'motor preset' under the axis your rotary motor is connected.. There's not much more to it, but perhaps I'm missing something? We're available during business hours via phone and virtually 24/7 via email at if there's something that's not making sense to you..

Understand that your not setting 'Aux A' to flip direction.. your setting I/O 1 to flip direction.. You have 2 I/O lines per Aux input. (Aux A = I/O 1 and 2 -- Aux B = I/O 3 and 4)

Jay Burlage 0 votes
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I had configured the motor settings manually, as I’m using non-DP gear motors

Oh... well you did not tell me that! You basically left out THE most important detail... So you've got your own motor.. What exactly is your 'rotary' then? Is it our Stage R or is it your own custom setup?? What is the specifications of the motor you are using?? Exactly what custom motor settings were you using?

I could get it to work for a bit and then the rotary axis would just stop cold after a cycle or so.

So everything appears to be running properly at the MX3 but only one custom motor has stopped? Is the other motor your running our motor or yours as well?

I'm wondering if there is a limit as to how many times (or length of time/travel) that limits how many times

Nope.. Unless you set the 'max shots'..

I did a keyword search of the term ‘rotary’ in the MX3 manual pdf, but there was not a lot of explanation of what it is, how it should be used and what relations the degrees/inches/centimeters numbers have in a rotary setup

I guess you completely missed section 7.1.2 "Setting up Axis manually", since you have your own motor you would be setting up the axis manually... In that section it says

If you’re using DIY or 3rd party equipment with the MX3, you may need to configure your axes manually. To do this, you will edit the RPM, Ratio, and Rotary parameters directly.

RPM is the number of output rotations per minute of your motor. This is after any included gearbox in the motor. It is literally the number of rotations per minute of the output shaft that your motor can produce.

The ratio is either the input rotary reduction ratio for rotary (pan/tilt) axes, or the travel per rotation, in inches for the linear (dolly) axis. For example, if you have a rotary table that has a 100:1 gear reduction, you’d enter 100.0 in this parameter. If you were to have a linear drive based on a pulley, you would enter the pitch diameter of the pulley, in inches
for this parameter.

An on/off flag that specifies whether the axis is a rotary axis, or a linear axis. Controls how speeds are displayed either as degrees, or as inches/centimeters.

Is there anything specifically that you don't understand? As you can see from the "Rotary" on/off the manual explains that if you set the axis to rotary the controller shows values in Degrees... If you turn the rotary setting off for the axis the controller will show inches/centemeters depending of course on the inch/cm unit setting... I'm not sure what else there is to know or what might be confusing about that?

I set the required rpm, rotary, and ratio settings but not sure what function or relationship the travel degrees numbers represent or what function those settings have, or if they should even be changed at all?

It's quite simple... If your in the main motor screen, for continuous motion the main value represents 'degrees per minute'.. if your in SMS mode it represents 'degrees per move'. Certainly their function is to set a speed in degrees per minute, perhaps I'm not understanding what your asking here?

Again: We're available during business hours via phone and virtually 24/7 via email at if there's something that's not making sense to you..

Jay Burlage 0 votes
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Some general statements:
-It seems to me you have your motors backwards.. you should be using a higher rpm motor for the dolly and a lower rpm motor for your rotary..
-35 RPM seems on the fast side for a rotary unit even with a 5:1 reduction.. As a matter of reference we recommend our 3 RMP motor for our Stage R and the unit has about a 3:1 reduction.. Our 8 RPM motor is actually pretty quick on the Stage R..

Axis 2 (Panning)
Panning motor: 35 rpm gearmotor connected to a reduction gear assembly with 5.25:1 step-down ratio
RPM: 35
Ratio: (based on gear reduction unit) 5.25
Rotary: On

What is the rated Voltage and rated Amperage on this motor?

I could for example set the MX3 to control the panning motor to turn, let’s say, 120° over a duration that matches the duration set to go between limit switches

Okay simple math here.. lets say it took 20 seconds to travel between the two limit switches.. so you desire 120d per 20 seconds.. If we convert that to degrees per minute (60x120/20) we get 360, so you would set the axis to approximately 360 degrees per minute..

I’m not sure if you are saying that these distance/degree numbers are set automatically, or if I have to alter those numbers (deg or distance)?

You set the distance or degrees per minute on the main motor screen... Say you want 20 degrees per minute. You set the axis to 20 degrees per minute.. I'm not sure why this is so confusing..

What is the difference in results if you set the deg/distance numbers on the main menu using the Up/Down buttons versus the left-button, left-button, Axis menu, Set Distance per Hour menu to alter them? I wasn't clear about that.

Super simple.. In the main motor screen (in continuous mode) you are setting 'distance per minute'... okay.. OR you can also set the 'distance per hour' in the axis menu.. They are the SAME thing.. just different scales.. So for example if you set the distance per hour to 360 degrees you'll notice when you return to the motor screen it will show 6 degrees per minute.. Now lets say you change the 6 degrees per minute to 12 degrees per minute and you then go into the axis menu the distance per hour will be 720. Nothing mysterious or crazy, just simple math and two ways of setting the same value. Sometimes its just easier to do the math for a distance per hour vs a distance per minute.

Jay Burlage 0 votes
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Hi Jay,

Your explanation makes perfect sense. I guess I was reading too much into the process. I was worried that I needed to change something in terms of the deg to prevent the process from halting. I understand the math, etc. in terms of rotation but couldn't explain the stoppage.

I have tried it again and it seems to work fine. I can't repeat the problem earlier, so I have no idea what was causing it. Thanks again for your time and help!


Chuck Butler 0 votes
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