94 Application macrosPID control macroThe PID control macro is suitable for process control applications, for exampleclosed-loop pressure, level or flow control systems such as• pressure boost pumps of municipal water supply systems• level-controlling pumps of water reservoirs• pressure boost pumps of district heating systems• material flow control on a conveyor line.The process reference signal is connected to analog input AI1 and the processfeedback signal to AI2. Alternatively, a direct speed reference can be given to thedrive through AI1. Then the PID controller is bypassed and the drive no longercontrols the process variable.Selection between direct speed control (control location EXT1) and process variablecontrol (EXT2) is done through digital input DI3.The stop/start signals for EXT1 and EXT2 are connected to DI1 and DI6 respectively.A constant speed (300 rpm) can be activated through DI4.Default parameter settings for PID control macroBelow is a listing of default parameter values that differ from those listed in chapterAdditional parameter data (page 263).Parameter PID control macrodefaultNo. Name10.04 Ext2 start func In110.05 Ext2 start in1 DI610.10 Fault reset sel C.FALSE12.01 Ext1/Ext2 sel DI313.05 AI1 min scale 0.00013.09 AI2 max scale 1500.00013.10 AI2 min scale 0.00021.02 Speed ref2 sel PID out21.04 Speed ref1/2 sel DI326.02 Const speed sel1 DI426.06 Const speed1 300 rpm
