Hitachi L100 PID Control

3–18

“A” Group: Standard Functions

PID Control

When enabled, the built-in PID loop calculates an ideal inverter output value to cause a loop feedback process variable (PV) to move closer in value to the setpoint (SP). The current frequency command serves as the SP. The PID loop algorithm will read the analog input for the process variable (you specify the current or voltage input) and calculate the output.

•A scale factor in A_75 lets you multiply the PV by a factor, converting it into engineering units for the process.

•Proportional, integral, and derivative gains are all adjustable.

•See “PID Loop Operation” on page 4–32 for more information.

			“A” Function		Run		Defaults
	Func.	Name /		Description	Mode	–FE	–FU	–FR	Units
					Edit
	Code	SRW Display				(CE)	(UL)	(Jpn)
	A_71	PID Enable		Enables PID function,	✘	00	00	00	—
				two option codes:
		PID SW	OFF
				00 ...PID Disable
				01 ...PID Enable
Configuring ParametersDrive	A_72	PID proportional gain		Proportional gain has a range	✘	1.0	1.0	1.0	—
				of 0.2 to 5.0
		PID P	1.0
	A_73	PID integral time		Integral time constant has a	✘	1.0	1.0	1.0	sec.
		constant		range of 0.0 to 150 seconds
		PID I	001.0s
	A_74	PID derivative time		Derivative time constant has a	✘	0.0	0.0	0.0	sec.
		constant		range of 0.0 to 100 seconds
		PID D	00.0
	A_75	PV scale conversion		Process Variable (PV) scale	✘	1.00	1.00	1.00	—
				factor (multiplier), range of
		PID CONV	01.00
				0.01 to 99.99
	A_76	PV source setting		Selects source of Process	✘	00	00	00	—
				Variable (PV), option codes:
		PID INPT	CUR
				00 ...[OI] terminal (current in)
				01 ...[O] terminal (voltage in)

NOTE: The setting A_73 for the integrator is the integrator’s time constant Ti, not the gain. The integrator gain Ki = 1/Ti. When you set A_73 = 0, the integrator is disabled.