You can run PIDDEF with 0 for both the Ki and Kd and keeping only Kp. But since TBASIC doesn't run floating point math, you need to scale your Kp value into fixed point representation. So if you need 1 decimal place precision, Kp = 5 means 0.5. If you need 2 decimal place precision, set Kp = 50 which means 0.50