char *str = get_uart_string();

int parameterset;

float gain;

float coeff_a0;
float coeff_a1;
float coeff_a2;

float coeff_b1;
float coeff_b2;

int result = sscanf(str, "P%i_%f_%f_%f_%f_%f_%f#", &parameterset, &gain, &coeff_a0, &coeff_a1, &coeff_a2, &coeff_b1, &coeff_b2);