[Niclas]

I have to admit I'm a beginner with DC motors, I've only used step motors before. Anyway I now have a motor called Exmek Electric with the product no MB062FS107. This 24V DC motor has a built-in encoder with two Hall IC:s (se attachment).

The producers home page is http://www.exmek.com

Four pins are available and are called 1, 2, + and -.

Question 1) Should theese be connected to the Motor Mind 2 as follows ?
1 -> CHA
2 -> CHB
+ -> +5V
- -> GND
This would leave pin RC-I on the Motor Mind unconnected.

Question 2) Is it mode 4 on the MM2 I should use?

/Niclas

[Lon]

Niclas,

Do you have a link to a datasheet? I couldn't find the motor part you referenced on their web site. The encoder should be a quadrature type encoder with one signal out of phase with the other. The leading signal (a vs. is determined by the direction of motor travel.

Mode 4 is used for closed loop positions control with and encoder. The position is controlled via a serial interface to the Motion Mind in this mode.

Lon

[Niclas]

Hi Lon!

Thanks for helping out.

I tried the pin assignment above and it works. Unfortunately our motor is geared 1:69 which means we get 69 pulses on each lap. If I haven't misunderstood totally this is to inexact for us. 360/69 gives a resolution of over 5 degrees. We need to position our wheel in 1 degree steps. Am I right if I assume that we need a motor with more than 360 pulses per lap to get a one degree resolution?

Now we are looking into stearing with a potentiometer instead. I have found a 350 degree potentiometer. How does the MM2 control the motor in mode 5. If I need to go from position 350 to 15, does the MM2 reverse the direction and move backwards from 350 to 15 or does it go the shortest way and pass 350 -> 360 -> 15?

In the 350 potentiometer solution we would get a dead angle of 10 degrees where we don't know where we are. Am I right?

[Lon]

The Motion Mind is reading an analog feedback signal not degrees. If you ask it to go to 200 A/D counts it moves forward or reverse until it reaches 200 A/D counts. In other words it doesn't care what degree it's at.

I'm a little unclear on your encoder. Most encoders are mounted prior to gearing. If you are getting 69 counts per output shaft revolution, then you encoder is putting out 1 count per motor shaft revolution. That's pretty strange.

A typical encoder with say 500 counts per motor revolution would give you 34000 counts for each turn of your ooutput shaft.

Lon