I am using a TI F28069M to control a motor, with the simulink support package. On the motor shaft there is an incremental encoder installed. With the support pacakage i am trying to calculate the current speed of the shaft. I am using the eQEP block from the libary. I am able to get a position but i am having troubles getting a speed. In the Speed calculation of this eQEP block there are alot of settings. It is unclear to me how i should use these settings to obtain a rotationspeed (RPM). I looked at the examples from the MathWorks site but they are unclear to me. Do the different registers mean. I contacted MathWorks about this and they said that they only read the registers and dont know anything about it.
I look at some documents and they use the frequency of the A/B signals to calculate the speed. I tryed this my self with a real scope and measured the period of the signals at 100% and 30% duty cycle.
For 100% the period of the pulse was 65.6 micro seconds wich should be about 1829 rpm. 60/((65.6 * 10^-6)*500)
For 30% the period of the pulse was 232.63 microseconds which should be about 500 rpm.
The encoder i am using as an resolution of 500 and i am using the quadrature detection.
In Simulink i got a value of 5300 (30%) and 1430 (100%) from the qcprd output (eQEP Capture Period Register). Which calculation should i preform to obtain the correct speed?
Any help would be appreciated.
