61Magtrol Model DSP7000 Dynamometer Controller C h a p t e r 6 – Manually ControlledOperationOPERATIONNote: If the response is too slow or oscillatory, adjust the values for P,I and D. For more detailed instruction, refer to Chapter 4 – PIDSettings.6.5 how to set open loop Control1. beginning with the brake in the oFF position, press the oPEN LooP button. The openloop control menu should appear. See Figure 4–1 Open Loop Control Menu.2. Use and buttons and the Decrease/Increase dial to set a value of current equal to thepercent of full scale output.3. If needed, PoWER UNITS and DISPLAYED UNITS can be changed while in oPEN LooPmode. (For further instruction, refer to Section 6.1 – How to Set Desired Power Units.)4. Use the bRAkE oN/oFF button to turn the brake oN. (Note: When the brake is on, theonly thing that can be adjusted is the set point. There are no other active settings at thistime.)5. To exit the open Loop Control mode and return to the main menu, turn the brake oFF andpress the oPEN LooP button.6.6 how to set preload Control1. beginning with the brake in the oFF position, press the oPEN LooP button. The open loopcontrol menu should appear. See Figure 4–1 Open Loop Control Menu.2. Use and buttons and the Decrease/Increase dial to set the preload value of current equalto the percent of full scale output.3. Enable or disable PRELoAD function by pressing Scale D button.4. If the preload function is enabled, “*” indicator will be displayed as shown in Figure 6–5Preload function enabled.POWERBRAKE STATUS SET POINT SET POINT P I DTORQUE SPEED USER DISPLAY0.000 X 0.000 XX.XX 0OFF 0.00 %OPEN LOOPPRELOAD*Figure 6–5 Preload Function enabledDesired resultsThe dynamometer should load the motor under test. because the mode isopen loop, the controller will not stabilize on speed or torque, but will applya constant current to the dynamometer brake. The actual loading will changeas the brake heats up or as other external factors change. The PID’s have noeffect in this mode.
