Re: RAMPS device adapter - variable movement

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Re: RAMPS device adapter - variable movement

Nikita Vladimirov
Hi, Volko,

Your variable movement problem is most likely in hardware - your driver
chip may not provide enough current for your motor, so the motor skips
the steps. Try turning the small potentiometer for current control on
the motor driver board. The current mush be high enough to provide good
motor torque (no skipped steps), but not too high (or the motor will
become hot). I was able to achieve <1 um bidirectional repeatability
with RAMPS 1.4 and Thorlabs DRV001 motors, without significant backlash.

Nikita


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Re: RAMPS device adapter - variable movement

Straub, Volko A. (Dr.)
Thanks Nikita,
I set the potentiometer prior to connecting the motors using the instructions on the Pololu website (https://www.pololu.com/blog/484/video-setting-the-current-limit-on-pololu-stepper-motor-driver-carriers). However, it is possible that I set them a bit too low to be on the safe side. Unfortunately, I can't test this at the moment as I accidently managed to drive the motors past their limit stops by sending some direct GCode commands and now I can't move the stage at all as the motors appear to have disengaged from the spindle. Once I figured out how to fix this, I will give your suggestion a go.
Did your bug fixes in the RAMPS adapter actually ever made it into the Micromanager code? If not, do you have a compiled dll for Windows of your RAMPS device adapter code that you could share?
Cheers,
Volko


-----Original Message-----
From: Nikita Vladimirov [mailto:[hidden email]]
Sent: 16 August 2019 13:13
To: [hidden email]
Subject: Re: [micro-manager-general] RAMPS device adapter - variable movement

Hi, Volko,

Your variable movement problem is most likely in hardware - your driver chip may not provide enough current for your motor, so the motor skips the steps. Try turning the small potentiometer for current control on the motor driver board. The current mush be high enough to provide good motor torque (no skipped steps), but not too high (or the motor will become hot). I was able to achieve <1 um bidirectional repeatability with RAMPS 1.4 and Thorlabs DRV001 motors, without significant backlash.

Nikita



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Re: RAMPS device adapter - variable movement

Nikita Vladimirov
In reply to this post by Nikita Vladimirov
Hi, Volko,

I submitted a pull request, but not sure if it became a part of MM 2.0
code. Here is my latest code:

source code:
https://github.com/nvladimus/micro-manager/tree/master/DeviceAdapters/CNCMicroscope/RAMPSStage
64-bit Windows DLL file:
https://github.com/nvladimus/micro-manager/blob/master/mmgr_dal_RAMPS.dll

Best,

Nikita



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Re: RAMPS device adapter - variable movement

Straub, Volko A. (Dr.)
Dear Nikita,

I downloaded and tried your updated RAMPS device adapter code, but unfortunately it doesn't resolve the odd behaviour of the Z control in the stage control panel.

- Clicking the single arrow for the Z axis does not move the Z axis when the displayed position is <= 0 um (clicking double arrow up or down moves the stage)
- Clicking the single arrow for the Z axis reports movements of 5 um when step size is set to values between 2.5 and 5 um (no movement for step sizes smaller than 2.5 um)
- Clicking the double arrow down for the Z axis produces a reported move of 5 um less than the set distance when displayed Z position is negative.
- Clicking the double arrow up for the Z axis produces a reported move of 5 um more than the set distance when displayed Z position is positive.

Thanks for any comments/suggestions,
Volko

-----Original Message-----
From: Nikita Vladimirov [mailto:[hidden email]]
Sent: 18 August 2019 22:19
To: Micro-Manager General <[hidden email]>
Subject: Re: [micro-manager-general] RAMPS device adapter - variable movement

Hi, Volko,

I submitted a pull request, but not sure if it became a part of MM 2.0 code. Here is my latest code:

source code:
https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fnvladimus%2Fmicro-manager%2Ftree%2Fmaster%2FDeviceAdapters%2FCNCMicroscope%2FRAMPSStage&amp;data=02%7C01%7Cvs64%40leicester.ac.uk%7C0db53f3d970a446bea4d08d724226258%7Caebecd6a31d44b0195ce8274afe853d9%7C0%7C0%7C637017602414994267&amp;sdata=WqzPiLhunFiOevsU%2FpZR3E2orOEhm6VvuOPafRDwybg%3D&amp;reserved=0
64-bit Windows DLL file:
https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fnvladimus%2Fmicro-manager%2Fblob%2Fmaster%2Fmmgr_dal_RAMPS.dll&amp;data=02%7C01%7Cvs64%40leicester.ac.uk%7C0db53f3d970a446bea4d08d724226258%7Caebecd6a31d44b0195ce8274afe853d9%7C0%7C0%7C637017602414994267&amp;sdata=jgVPHLBRk7xoBzUT3Hl51vbXKn6AoaWnfa9co2ImHFU%3D&amp;reserved=0

Best,

Nikita



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