Controlling the speed of a Brushless DC Motor

I was wondering how possible it would be to take an Arduino and program it to control the speed a brushless DC 3 phase motor. I don't want to use a potentiometer, just using a time value to have the motor rotate fast or slow. The motor I am needing to use runs off of 24vdc. I understand the Arduino cannot supply that, but I have that taken care of.

I have the motor connected to a Anaheim Drive Board using the 3 phases and the Hall effect sensors. The board uses a external 0-5 input to control speed.

For example: I would like to set a time value of 6 minutes to go from point A to point B. After some calculations (already done) the Arduino would output 2.48v to the Anaheim Drive Board and then the motor would rotate accordingly.

How possible is this and if so, are there any examples of code that would demonstrate how to control PWM voltage without a potentiometer?

Let me know if you have any further questions, since I have NO IDEA where to start this part of my project

PWM doesn't change the voltage, just the duty cycle, so I suspect that you won't get it to work with your controller board without a potentiometer. You could have the Arduino control a digital pot for you though.

Digital pot? Could you explain that a little bit? I will be using a touchscreen, so I could POTENTIALLY use a slider bar, but I would like to avoid using a slider bar.

Preferably I would like to use up and down arrows to change my time values and the time value would be associated to a voltage.

If that doesn't make sense, let me know and I can elaborate better.

I was thinking of something like this.

Disclaimer: haven't used one.

You could use a DAC like this, 0 ~ 4095 in over I2C, 0 ~ 5V out.