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Replies: 5
Views: 1640
Overall Problem:
We have a need to drive a Bistable Rotary Solenoid to control a robot arm.
Components in the Solution: 1. TI, DRV8801 motor driver (DRV8801EVM board) 2. Atmel processor 3. Bistable Rotary Solenoid Overall Design The goal is to drive the bistable rotary solenoid CW and CCW using a PWM signal. The Enable pin is supplied a with a PWM signal. Phase signal is use to control CW and CCW. For this experiment the mode1 and mode2 pins are 0 and 1 respectively. Channel 1 - Out+ Channel 2 - Out- Channel 3 - Enable (PWM signal) Channel 4 - Phase In this scenario I am expecting Out- to have the compliment of the PMW signal seen on Out+. Base on the limited information I hope you can shed some light on the problem.
Components in the Solution:
1. TI, DRV8801 motor driver (DRV8801EVM board)
2. Atmel processor
3. Bistable Rotary Solenoid
Overall Design
The goal is to drive the bistable rotary solenoid CW and CCW using a PWM signal. The Enable pin is supplied a with a PWM signal. Phase signal is use to control CW and CCW. For this experiment the mode1 and mode2 pins are 0 and 1 respectively.
Mahendra,
I think a scope capture is missing from the post as I am not able to see it. Can you re-attach the image as a JPEG or BMP?
Also, you mention an Atmel processor, but also mentioned you are using an EVM. Did you try experimenting with the micro/software given with the kit before wiring in your signals from the Atmel processor?
Ryan Kehr
Motor Drive Application Manager
In reply to Ryan Kehr:
2275.DRV8801 Technical Support.doc
Hello Ryan,
I attached the complete file. I hope you can access this file.
Best Regards
In reply to Mahendra Gunawardena:
Hi Mahendra,
If you want to see the outputs opposing each other as you apply a PWM, the PWM must be applied to the PHASE input, not the ENABLE input. If you do this, you will be able to control the direction of actuation by going above or below 50% duty cycle.
When you PWM the ENABLE input, the outputs only oppose each other during the fast decay portion. This is what you have configured the device to operate at, but the scope capture is set to 200 ms per division, which is too coarse. Current decay often takes microseconds so if you zoom in, you should be able to see the outputs switching accordingly for a few microseconds.
Hope the info helps. Best regards,
Jose Quinones
When I got the EVM board it was modified internally within our company. I saw the board work. I don't have scope plots of the DRV8801 working using the TI micro MSP430 micro on the EVM.
In summary,
Thank you for your help.
Best Regard
Mahendra
In reply to Jose Quinones:
Thank for the response. Let me try your suggestion.