DRV 10983 EVM

Hi Jayant,

Milan has been notified. Can you confirm the voltage range of the 24V battery?

Hello Jayant,

The error message typically appears if USB to ANY is not properly connected to EVM or host computer side.

Please try again with new DRv10983 if it is damaged.

Best Regards

Milan-Motor Applicaiton Team

Sent from my iPad

Begin forwarded message:


From: Jayant Arora <arora.jayant@gmail.com>
Date: May 21, 2015 at 14:06:44 GMT+5:30
To: "noreply@mail.e2e.ti.com" <noreply@mail.e2e.ti.com>
Subject: Fwd: Motor Drivers Forum: DRV 10983 EVM


Milan,


This is further to my mail earlier mail.

Having used the Runtian motor to understand the functioning of the EVM, 10983 and also used another motor successfully now I am to yet another motor. Having come to something which I need to understand, I seek your help to speed up my learning process.


While on the job, I have following observation to make. Please see the snap shot of GUI. ( i have not been able to attach file)


Upon searching related web pages, I could not find what the error codes relate to. Please send me a list.


I am also sending the .CSV file, ( I have not been able attach this also ) you will notice the motor is spinning in open loop. Upon further checking I found it does not do so in close loop. Any comments or suggestions on this, please?

May I also know why the speed in Hz and electrical period in micro second do not relate to each other?
23.4 Hz ought to mean per 42.7 m Sec, right?


Cheers,


Jayant

Sent from my iPad

Rick,

The voltage of battery could range between 22.5 and 25.2. At the time of testing it was 23.9 V.

I hope this is in line with your query.

Cheers,

Jayant

Hi Jayant,

Yes, this is in line with my query. Sometimes the voltage range of the battery is overlooked.

Hello Jayant,

On EEPROM Programming: If you are succesfully connected to DRV10983 on EVM via GUI, than for EEPROM progamming, just need to make sure:

1. Apply 24 Volt >22V

2. Insert EEPROM key 0xB6 and click EEWrite. This will program the EEPROM with latest tuned parameter of GUI.

On tuning your custom motor:

1. I would suggest to follow flow-chart steps of tuning guide: http://www.ti.com/lit/ug/slou395b/slou395b.pdf

2. ITo provide right inputs, I would need to know the GUI basic and advance page setting . I could not see your attachement, not sure why you could not able to attach it. Please try again.

also let me know followings for your motor:

1. Motor rated voltage and current
2. Rated speed- rpm
3. Number of poles
4. Back-emf or velocity constant
5. Motor phase to neutral or center-tap resistance value.

Error between Freqeuncy in Hz and time period in usec: There could be division trunctation errors due to fixed point division.  For best accuracy in speed calculaiton, use FG output.

Best Regards

Milan

Milan,

Thanks for the quick response.

Please note the voltage is 23.9 and key xB6 was entered than click on eeWrite gets me prompt power supply voltage should be greater than 22V.

While using our motor I followed the slou395b and only after that posted my observations.

I was using iPad and could not attach the snapshots, I will try to send again using laptop.

In the meanwhile following are the parameters set on different screens.

Adj mode half cycle
Closed loop acceleration 0.77 Vcc/s
Control coefficient setting. 1
Commutate advance control constant
T control advance (s) 320 u

Enable initial speed detected ticked
Initial speed detect threshold 0.8 Hz

Enable reverse drive not ticked

Align time 5.3 sec, I will reduce it later after more trials.

First order ace 0.3 Hz/ s
Second order acc 0.22 Hz/ s
Open to close loop threshold 8 Hz
Open loop current rate 6 Vcc/ s
Open loop current 1.6 A

Close loop not ticked

Acceleration current limit 2.6 A, I will reduce it to 2 A later after more trials

Phase resistance 1.54. Will reduce to actual later after trials

Phase to phase Kt 254 MV/ Hz. I tried to reduce it to 356 the value as seen on Display screen and motor stalls after some time

On to specifications of the motor.

The rated voltage and current are 24 V, 1.5 A
RPM 300
Poles 12
Velocity constant 356 mV / Hz
Winding resistance 1.25 ohms

I hope above will suffice for you to assist me go further.

Thanks again

Cheers,

Jayant

Milan,

Sorry for bothering you. I could not find drop down menu on iPad for inserting media or even paste button to add Word files.

Anyway on laptop I found these and i have added the three snap shots for your perusal. I hope these with the mail sent earlier will give you better picture at all that is going on at our end.

While in my mail I said I will change the phase resistance and the Kt near to the values mentioned under the motor parameters, the changes reflect in the snap shots.

Another thing that is bothering me is the Speed Command% and Speed cmd Buffer not being nearly same value even after Kt was changed to the value near to what is found on Display. Can you please some throw some light on this aspect as well.

Sorry for bothering you with many questions.

Cheers,

Jayant

Jayant,

Check both the Disable the Sleep/Standby Mode box and the OverRide box, enabling speed command by I2C. Also I hope you have measured the correct value of back-emf constant as described in tuning guide. If you can share the back-emf waveform of motor terminals during caosting, I would be able to confirm it.

Lets flow-chart given in tuning guide, first tune start-up setting to get successful open-loop operation. To do this,

- Enable, CLoopDis by selecit it, de-select Enable IPD and Initial speed detect.

- Disable acceleration current limit.

- start with lowest values of  first/second order accelerate and gradullay increase it to get faster rates.

- Select open to close loop thersold, 1/4 to 1/5 of rated electric Hz of motor, for example if rated Hz if 100, you can select the thersold between 20 to 25Hz.

- Control the speed via GUI on display page and check the motor is able to reach thersold value smootly in open loop.

 

Best Regards

Milan

Milan,

Thanks for your response and advice within.

That I was away for a few days, my colleague worked in my absence and has motor spinning well. On the  face of it everything looks good but I have few queries.

How can I get the speed command and speed command buffer to near same values? In our case now they are 100% and 51.37 % . Playing around with  T control advance did not improve on them being nearly equal. Can you please assist?

Secondly the  writing on eeprom does work as yet. The supply voltage being 24 V, upon clicking on write we yet get prompt  asking for making sure that voltage is more than 22V. This has been a contentious issue from the day one that I acquired the EVM.

Can you please advice as to how can this be overcome?

Cheers,

Jayant  Arora

Jayant,

Refer to section 6.2 to know the deatil of reducing the gap between command value and buffer. Also make sure that closed loop is enabled at basic setting page, otherwiese motor always rotate at open to close loop thersold irresepective of speed command.

I would also suggest not to worry to much about it and check FG speed feedback, if it mactches speed command and motor is not taking current within limits, it an indication of optimized tuning.

EEPROM wiriting: you will always get message to increase the voltage >22V even applied voltage is 24V, just click to proceed, EEPROM will be written. Make sure to enter B6 EEPROM key code, before writing.

Best Regards

Milan

Milan,

I am back with another query. I have been working on this project for sometime as you will see from earlier mails. Thanks for your help that I progressed and have used the controller in our products which are undergoing field trials.

I have a little unusual observation to report and seek your help.

With one of the motors we achieved desired speed of 250 RPM and so far things have been working to our satisfaction.

Lately controller, motor, power supply being in good working condition we have not been able to reach the desired speed. The maximum we have been able to achieve it 140 RPM. With all the experience we have gathered we are not able to reach 250 RPM.

The mechanical AVS is not enabled and Acceleration current limit is set to 1.6 A, the running current of motor being 1 A.

The Speed command buffer is hovering around 40%, which is obvious indication of lower duty cycle and as such speed being lesser. The speed control is analog and speed control potentiometer is set for maximum speed.

Would you guide me as to what else I should look for in the reason behind slow speed?

Cheers,

Jayant Arora

Jayant,

Can you turn off the close loop current limit and see whether duty cycle limiting around 40% goes away?

I saw that you already have disabled the mechanical AVS, pleas leave it turned off while you have turn off close loop current limit.

Seil

Milan,

Thanks for all the help in the past.

We have successfully used small lot of prototypes of motors of 45, 25 and 12 W.

Now we would like to handover the designs to our production team.

I need your help and advice.

Can we push the power rating of first motor to 50 W without sacrificing reliability of DRV 10983 controller? What extra precautions  would you suggest in matter of heat dissipation?

We have bought target board and Launchpad  430G2 for programming the DRV before assembly. Where can find the  guide to use  target board with Launchpad?

Your assistance will be appreciated.

Thanks and regards,

Jayant Arora

Seil,

 

Please excuse me for delayed response.

 

May I know where is the option to disable close loop current ? I checked the GUI and did not find

any. Please let me know.

 

Cheers,

 

Jayant Arora

Sent from my iPad

Jung Chun Sik,

To store parameters in excel  press save on GUI

Regards,

Krushal