DSP28335 2812 speed_frq.pdf

Digital Control Systems (DCS) Group 1 Texas Instruments Description This module calculates the motor speed based on a rotor position measurement from QEP sensor. Availability This IQ module is available in one interface format: 1) The C interface version Module Properties Type: Target Independent, Application Dependent Target Devices: x281x or x280x C Version File Names: speed_fr.c, speed_fr.h IQmath library files for C: IQmathLib.h, IQmath.lib Item C version Comments Code Size□ (x281x/x280x) 104/104 words Data RAM 0 words? xDAIS ready No XDAIS component No IALG layer not implemented Multiple instances Yes Reentrancy Yes ? Each pre-initialized “_iq” SPEED_MEAS_QEP structure consumes 20 words in the data memory □ Code size mentioned here is the size of the calc() function Speed Calculator Based on Rotor Angle from QEP sensorSPEED_FRQ SPEED_FRQ ElecTheta Speed SpeedRpm Digital Control Systems (DCS) Group 2 Texas Instruments C Interface C Interface Object Definition The structure of SPEED_MEAS_QEP object is defined by following structure definition typedef struct { _iq ElecTheta; // Input: Electrical angle Uint32 DirectionQep; // Variable: Direction of rotation (Q0) _iq OldElecTheta; // History: Electrical angle at previous step _iq Speed; // Output: Speed in per-unit Uint32 BaseRpm; // Parameter: Base speed in rpm (Q0) _iq21 K1; // Parameter: Constant for differentiator (Q21) _iq K2; // Parameter: Constant for low-pass filter _iq K3; // Parameter: Constant for low-pass filter int32 SpeedRpm; // Output : Speed in rpm (Q0) void (*calc)(); // Pointer to the calculation function } SPEED_MEAS_QEP; // Data type created typedef SPEED_MEAS_QEP * SPEED_MEAS_QE