MD30C Current Draw Problem

Autonomous Robot, Manual Robot, DC Motor Driver, Stepper Motor Driver, Servo, Multi PWM chip.....

MD30C Current Draw Problem

Postby Tunaz » Wed Jan 28, 2015 11:37 pm

Hi,

My current set up: Arduino controlling speed(PWM pin) and direction(digital pin) of the motor through the MD30C controller which is wired to a 12v SLA battery.

Issue: My motor isn't able to draw enough current to carry on load. (Sending of analogwrite 255[max speed] isn't sufficient)
However, if I power my motor directly via the 12V SLA, it is able to draw enough current to produce enough torque to carry on my load.

So I would like to be able to achieve the same result through the MD30C.
May I ask how can I produce the same amount of power/torque through the MD30C as it is limiting my current supply to my motor.

Thanks for any help!
Tunaz
Newbie
 
Posts: 8
Joined: Wed Jan 28, 2015 11:29 pm

Re: MD30C Current Draw Problem

Postby waiweng83 » Thu Jan 29, 2015 10:09 am

Please make sure the jumper position is on "External PWM".
You can also try pressing the push button A or B, does the motor run at full power?
With the power of dream, nothing is impossible...
User avatar
waiweng83
Moderator
 
Posts: 155
Joined: Wed Apr 15, 2009 2:17 pm

Re: MD30C Current Draw Problem

Postby Tunaz » Fri Jan 30, 2015 4:43 pm

Yes, I have connected JP 4 to EXT POT and JP6 to EXT PWM.

When I press A or B, the motor goes to FULL power/desired power. However when I send PWM signal from my arduino, it is much weaker.

Thank you once again
Tunaz
Newbie
 
Posts: 8
Joined: Wed Jan 28, 2015 11:29 pm

Re: MD30C Current Draw Problem

Postby ober » Mon Feb 02, 2015 10:56 pm

Can you check the voltage at the PWM pin when the Arduino is giving full duty cycle PWM to the motor driver?
Ober Choo
Cytron Technologies Sdn Bhd
www.cytron.com.my
User avatar
ober
Moderator
 
Posts: 1352
Joined: Wed Apr 15, 2009 1:03 pm

Re: MD30C Current Draw Problem

Postby Tunaz » Thu Feb 05, 2015 1:52 pm

The output voltage at the PWM pin at max is 2.6V.

I am currently using Arduino Nano v3.1/Atmega328 to power 4 MD30C with the control of PS1 controller. After switching the GND of the PS1 controller to the other GND of the Arduino board, I managed to increase the max voltage at the PWM pin to around 3.3V. After disconnecting all except one MD30C's GND pin to the arduino, the max voltage increase to about 3.7V.

But with all of the GND pins connected to the same GND on the arduino, the output voltage at the PWM pin is only 2.6v.

Please advise, I believe I am suppose to draw out 5v of output at max PWM.
Tunaz
Newbie
 
Posts: 8
Joined: Wed Jan 28, 2015 11:29 pm

Re: MD30C Current Draw Problem

Postby ober » Thu Feb 05, 2015 5:27 pm

Mind sharing photos of the hardware setup? Sound weird. It might be you are not supplying sufficient current to the system.
Ober Choo
Cytron Technologies Sdn Bhd
www.cytron.com.my
User avatar
ober
Moderator
 
Posts: 1352
Joined: Wed Apr 15, 2009 1:03 pm

Re: MD30C Current Draw Problem

Postby Tunaz » Thu Feb 05, 2015 10:25 pm

I have attached the picture as requested.

May I check whether it is possible to use analog pins from the arduino to the PWM pin of the motor controller?
The analog pins are able to produce around 4.6V.

I have tested the arduino without any load and it seems to be able to supply 5V just fine.
Could it be an error in the coding?
Attachments
DSC_0018.JPG
Full set up- Two 12V SLA in parallel powering the project
DSC_0015.JPG
MD30C
DSC_0017.JPG
One out of the 4 controllers+motor+wheel setup
Tunaz
Newbie
 
Posts: 8
Joined: Wed Jan 28, 2015 11:29 pm

Re: MD30C Current Draw Problem

Postby ober » Thu Feb 05, 2015 10:53 pm

Good work! But can you share a clear photo of Arduino NANO? How it is being powered?

ADC pin is input pin, you want to use output to generate PWM. You get 4.6V at ADC because it is configured as digital output :) Only PWM pin can generate PWM for motor driver, and by control PWM duty cycle you get different speed at motor. You can use any digital output pin, but you cannot generate PWM and therefore cannot control the speed.

I guess is the battery does not have sufficient power for the whole robot. Can you use separate battery for Arduino Nano?
Ober Choo
Cytron Technologies Sdn Bhd
www.cytron.com.my
User avatar
ober
Moderator
 
Posts: 1352
Joined: Wed Apr 15, 2009 1:03 pm

Re: MD30C Current Draw Problem

Postby Tunaz » Fri Feb 06, 2015 11:04 am

The arduino is being powered by a separate 9V battery. However, I can also hook it up in parallel with the 12v SLA battery.

I believe the analog pins are able to write HIGH or LOW which generates 5v or 0v signal output. I am aware that I will not be able to control speed if I connect this to the PWM pin on the controller. If I cannot get the PWM output voltage to increase, I am fine with not being able to control the speed of the motor. Just want to check whether the controller will be able to take in this analog signal?

I will upload the picture of the arduino as soon as I am able to take a picture of it.
Tunaz
Newbie
 
Posts: 8
Joined: Wed Jan 28, 2015 11:29 pm

Re: MD30C Current Draw Problem

Postby ober » Sun Feb 08, 2015 11:42 am

Normal 9V battery will dry out very fast, not really recommend during development. Try to hook up another power source which you are sure to be stable, adapter or another SLA is good. Parallel with the SLA for motor is not recommended too. When motor need more energy, the voltage will drop and not stable.

Yes, Analog pin can be digital output pin, but it cannot be analog output pin. If you do not need PWM, you can utilize any pin for digital output, not necessary to be analog pin.

The motor driver do not accept Analog voltage for speed control, just PWM.
Ober Choo
Cytron Technologies Sdn Bhd
www.cytron.com.my
User avatar
ober
Moderator
 
Posts: 1352
Joined: Wed Apr 15, 2009 1:03 pm

Next

Return to Robot Controller

Who is online

Users browsing this forum: No registered users and 6 guests

cron