Stackshot New Motor Connector Specification

GoJian · Post by **GoJian** » Wed Oct 26, 2016 6:02 am

Dear all -

I have been working on a project to interface a Cognisys Stackshot controller with a few stepper motor operated macro rails I built myself. I suppose this also applies if you have other open source macro rails and would like to use the Stackshot controller to operate them.

Well I already have my macro rails working with an Arduino based controller. But I like the Stackshot controller (I bought the 3X version) because of its ease of use, portable and being able to adjust for motor currents through software.

My major difficulty right now is this new connector interface. Cognisys calls it "4-pin twist-lock type connector", which I have a picture of.

It is an upgrade from the original 4-pin mini-DIN (S-Video like) connector for the older version macro rail stepper motors, according to Cognisys webpage https://www.cognisys-inc.com/products/s ... nector.php.

I initially thought that these are just normal 4-pin twist-lock connectors and found a supplier on eBay (http://www.ebay.com/itm/171428887576). I ordered it, but it did't work. The pins are too thick and the spacings are incorrect. If you look carefully, the Cognisys connectors have the 4 pins in a "rectangle", not a perfect "square".

So now I am a bit lost. I have looked everywhere for specifications of these connectors. If you have any information about them, especially where to acquire the parts, etc., I would be very interested to know. I will also try to contact Cognisys directly and post back what I find out.

Grahame · Post by **Grahame** » Wed Oct 26, 2016 4:42 pm

Probably their own connectors.
Run a multi meter over the pins and find out what voltages are on each pin.
No grantee they conform to any standards.
Cut the end off that attaches to your rail and wire one of the square ones on with the v correct for your rail.
May be easier than that, this is from the above link
"Please make certain that if you are a current StackShot owner and you want to add a motor or new rail to StackShot that you get the correct cable. We have adapter cables available should you need them, just let us know."
So possibly just another cable.
I'm a tinkerer and prefer to roll my own

rjlittlefield · Post by **rjlittlefield** » Wed Oct 26, 2016 7:52 pm

See http://www.photomacrography.net/forum/v ... 216#185216

--Rik

GoJian · Post by **GoJian** » Thu Oct 27, 2016 5:59 am

Thanks Rik! Should have searched the forum more for answers before posting

I also got a reply from Cognisys.

"I am not aware of any distributors that offer the connectors we use in low volumes. We can however sell you any connectors that you might need. The cost for the connectors is 5$ ea. Both male and female connectors are available as cable ends that will need to be soldered to the cable or motor you plan to use. We can also provide you with the pinout of the stepper motor connection." -- Paul DeZeeuw

I will probably order a few cable end connectors and make a bunch of adapters converting from the Cognisys connector to my own "now standard" square 4-pins which I will use for all of my future motors.

Was really hesitating to cut the factory connector for a few days (...resisting the temptation

I kind of liked the nice-looking, water-tight seal of the original cable -- I might take it out for field work some day, but thanks Grahame for the suggestion. I hope one day I can make a Stackshot 3X myself, then I will be totally free.

--AdminCS edited to avoid exposing an email address to spambots

RickyTerzis · Post by **RickyTerzis** » Tue Aug 22, 2017 10:33 am

Hi....i am a new user here. As per my knowledge you should Run a multi meter over the pins and find out what voltages are on each pin.No gurantee they conform to any standards.Cut the end off that attaches to your rail and wire one of the square ones on with the v correct for your rail. In my case I had the issue and the connectors were embedded on PCB and it was difficult to remove them in case of any issue. Going forward i am going to concentrate on PCB assembly and its design, so that I can easily test and take the connectors out whenever required and can troubleshoot the motor issue.

ChrisR · Post by **ChrisR** » Tue Aug 22, 2017 3:07 pm

GoJian I'd be glad to hear how the conversion goes. IE, Do the sockets fit the control box nicely?
I never did buy those $85 worth of cables

mawyatt · Post by **mawyatt** » Tue Aug 22, 2017 4:48 pm

No need to cut the Stackshot cable. Just order the connectors from Paul at Cognisys and get mating connectors for your specific stepper motor. Then you make a "jumper" cable from the Stackshot cable to your specific cable for you motor, or if the motor has a connector built in then make the jumper to that connector on the motor. Either way you'll need to get the specific connector for your motor/cable.

I've done this for WeMacro motors and rails, MJKZZ motors, and rails and the modified THK KR20 rails.

This way you don't harm the Stackshot cable.

Hope this helps.

Best,

Mike

concon · Post by **concon** » Sun Sep 17, 2017 7:41 am

Does anyone know if their policy has changed? I contacted Cognysis last week and Paul simply linked me to their motor on his site and suggested I use that over the MJKZZ.

Using the StackShot controller and a 1.8 degree stepper motor with a pitch of 1mm you can expect a minimum step size of 0.3125um.

I spent a day trying determine if I could just adapt the stepper 4 pin to whatever locking connector they use, but without an actual connector specified I really don't want to make anymore blind purchases.

I mentioned that I had a THK rail and adapter kit that came with a 400 step/rev motor that I wanted to use, but it didn't seem like that was an option he could help me with

mawyatt · Post by **mawyatt** » Sun Sep 17, 2017 8:23 am

See if Paul will sell you a few of the connectors that the Stackshot Controller uses, then you can just make your own "jumper cable". Make sure you get both male and female, and get a few so you can make these cables for other focus stacking rail systems in the future.

If you want to change the stepper motor on the Stackshot rail, then I would follow Paul's advice and use the stepper he supplies (no jumper cable required). If it's for a completely different focus rail, then the stepper motors from Peter (MJKZZ), or William (Wemacro), or even from eBay or Amazon will require the appropriate connector for that particular motor.

The Stackshot Controller is really a good stepper motor controller, especially when mated to Zerene, this provides just about every feature for stacking needs. The Stackshot focus rail is a superb rail for lower magnification work, but for higher magnification use the modified surplus THK KR rails working with the Stackshot controller are the best option IMO.

Best,

Mike

concon · Post by **concon** » Sun Sep 17, 2017 11:31 am

Thanks for the reply. I'll try him again (already bought the motor during my last interaction with him). I already have the THK rail setup with the MJKZZ kit and motor. I've been using the stackshot for a little over a year but have recently moved to 80x - 100x imagery, thus the transition. I'm surprised he didn't offer me the parts that you're describing with my first communication with him, but will give it an go on Monday. He did say he was going to include a few cables with my order so I may be able to make due with those and splice something together.

mawyatt · Post by **mawyatt** » Sun Sep 17, 2017 12:33 pm

See below:

https://www.photomacrography.net/forum/ ... highlight=

You just need the Stackshot male connector to work with the NEMA 17 motor Peter provides with the kit which has only the motor connector wired. Simply solder the wires onto the Stackshot male connector as shown in the other thread and you are good to go. Make sure you do this carefully and don't short out any pins, if you aren't familiar with small electronics and soldering, find a friend that is, or electronic repair shop to prepare the cable.

Also, consider mounting the THK onto an ARCA rail instead of the brackets. His brackets are good but limit you to the T rail system, which doesn't have lots of options I've found.

With the ARCA mount, this allows a quick release but maintains a very secure rail attachment if you use a long ARCA rail and similar quality clamp which uses the standard 1/4-20 threads. Also allows easy coarse adjustments of the camera/lens assembly.

Best,

Mike

concon · Post by **concon** » Tue Sep 19, 2017 2:28 pm

Thanks again for the info and reply. I got everything today and decided to make a jumper cable as you suggested. I'm terrible at soldering, but fortunately my gf is big into racing drones so she had great hands for it....Only problem is I misunderstood either the Cognysis diagram or Peter's labeling and everything is put on reversed (back moves the rail forward and forward back, HA!). I suppose I could just turn the motor upside down and it would work correctly.

I currently use an extrusion setup and was looking forward to mounting the rail via his brackets; however, I have series 45 bars and it looks like his was made for 20 so they didn't fit. I actually ended up using one of the long arca clamps and clamping straight onto the rail (totally works for the time being). Most of my setup is mounted via arcas for modularity and easy transport to clients.

I obviously have a bit of reworking to do, but it's all moving and such. I was reading that the Stackshot controller can be configured to set the new rail thread size (1mm). Is this setting the rev/distance setting listed under the advanced configuration?

Last question- it's fairly loud (turned off high precision, torque to 1 which helped). Normal or might I have something that needs better securing?

Always appreciate your help!

mawyatt · Post by **mawyatt** » Tue Sep 19, 2017 5:23 pm

You can probably just reverse a pair of wires in the jumper cable, should be the ones that drive the coils in the motor. Use an ohm meter to identify and swap them.

Yes the Stackshot controller has the ability to program the 1mm thread pitch and the 400 step motors as well. I use Zerene for controlling the stepper thru the Stackshot controller. After you've got the correct parameters entered for your motor and rail. Move a specified distance and measure to make sure things are correct.

You can mount the ARCA plate directly to the THK KR rail without modifying the rail. Just drill and tap the ARCA plate with the correct holes.

Yes the THK rails are somewhat loud. This is really only an annoyance during long rail moves, during stacking with small steps its not too bad.

Best,

Mike

concon · Post by **concon** » Mon Sep 25, 2017 9:21 am

After adjusting the settings within the advanced configuration I was expecting to see the step size change when getting a stack ready; I had expected the 1um minimum step size to adjust to a new step size determined by the controller with the given input parameters. I'm reading the instructions to my best of my ability (haven't found a place they reference using a different rail, and have reached out to their support. I imagine that the 1um is a hard limit within their controller, based on my experience so far. I continue to see Zerene being being mentioned- is this a necessity to accurately see the new step size?

Thanks again- almost there!

mawyatt · Post by **mawyatt** » Mon Sep 25, 2017 11:24 am

Concon,

I only use the Stackshot Controller with Zerene, not stand alone. Maybe someone that uses it stand alone can comment.

Best,

Mike