113Magtrol Model DSP7000 Dynamometer Controller C h a p t e r 10 – TheoryMAINTENACNCEThe speed correction factor is calculated on each entry into the PID loop equations.Speed Correction Factor = - 0.0001 * x * 2 + 0.0203 * x + 0.005 limited to 0.051 to 1where x = RPM / NoMINAL SPEED * 100NoMINAL SPEED is set by the user and obtained from the data sheets for the dynamometer or brake.10.1.3 equaTionSWhere Skp, Ski and Skd are system coefficients…Yd(t) = (e(t) - e(t-3) + 3 * (e(t-1) - e(t-2))) * (10/Skd) * D%Yp(t) = (e(t) + Yd(t)) * (10/Skp) * P%Yi(t) = Yi(t-1) + (e(t) + Yd(t)) * (10/Ski) * I%Yt(t) = Yp(t) + Yi(t)Ys(t) = Scale * Yt(t)10.2 additional sCale faCtorThe Additional Scale Factor is a multiplier of the P, I or D term. Due to the fact there are so manydifferent dynamometer types and motor combinations, this multiplier is needed to extend the rangeof the PID. The letters represent the following:A = 0.001 F = 0.5b = 0.005 g = 1C = 0.01 h = 5D = 0.05 I = 10E = 0.1In using the multiplier, the user can input PID numbers from 0.001 (.001 x 1%) to 990 (10.0 x 99%)with good resolution.10.2.1 H ow T o SeT aDDiTional SCale faCTorbefore following the setup instructions, the values that must be set will need to determined. Thiswill depend on which testing instrument has been chosen for the configuration. For appropriatesettings, refer to the guide provided in Appendix D: Additional Scale Factor Table. once the propersettings have been determined, proceed with the following instructions for setup.10.2.1.1 Setting Additional Scale Factor for P (Proportional Gain)1. Press ShIFT then the P button. Use the dial to change value (A, b, C, D, E, F, g, h and I).2. once the letter is chosen, press ShIFT to return to the main menu.10.2.1.2 Setting Additional Scale Factor for I (Integral)1. Press ShIFT then the I button. Use the dial to change value (A, b, C, D, E, F, g, h and I).2. once the letter is chosen, press ShIFT to return to the main menu.10.2.1.3 Setting Additional Scale Factor for D (Derivative)1. Press ShIFT then the D button. Use the dial to change value (A, b, C, D, E, F, g, h andI).2. once the letter is chosen, press ShIFT to return to the main menu.
