I have a project. I need to calculate speed of DC motor. But i dont have encoder. Because My encoder was broken. I can calculate speed when i have PWM ? i use Arduino Uno and DC motor DSE38BE27-001. Please help me ! Thank in advance !
phamviethoa:
I have a project. I need to calculate speed of DC motor. But i dont have encoder. Because My encoder was broken. I can calculate speed when i have PWM ?
You need an encoder to measure the speed of your motor.
You can attempt to come up with some sort of table between PWM and speed but this won't be accurate.
I can calculate speed when i have PWM ?
Probably not in a reliable way.
How accurate do you need to be?
If you measure the current and use the correct H-bridge mode then you can calculate speed
quite well for a motor. The H-bridge mode has to be linear, so that the time-averaged voltage
is known. This means using synchronous rectification mode.
The voltage across the motor terminals = kw + IR
where k is the motor constant, w is the angular velocity, I and R are current and winding resistance
(compensated for temperature ideally).
But frankly an excoder or tachgenerator would be easier...