Hitachi L2002 PID ON/OFF and PID Clear

4–28

Using Intelligent Input Terminals

PID ON/OFF and PID Clear

Operations and Monitoring

The PID loop function is useful for controlling motor speed to achieve constant flow, pressure, temperature, etc. in many process applications. The PID Disable function temporarily suspends PID loop execution via an intelligent input terminal. It overrides the parameter A071 (PID Enable) to stop PID execution and return to normal motor frequency output characteristics. the use of PID Disable on an intelligent input terminal is optional. Of course, any use of the PID loop control requires setting PID Enable function A071=01.

The PID Clear function forces the PID loop integrator sum = 0. So, when you turn ON an intelligent input configured as [PIDC], the integrator sum is reset to zero. This is useful when switching from manual control to PID loop control and the motor is stopped.

CAUTION: Be careful not to turn PID Clear ON and reset the integrator sum when the inverter is in Run Mode (output to motor is ON). Otherwise, this could cause the motor to decelerate rapidly, resulting in a trip.

Option	Terminal	Function Name	Input			Description
Code	Symbol		State
23	PID	PID Disable	ON	Disables PID loop execution
			OFF	Allows PID loop execution if A71=01
24	PIDC	PID Clear	ON	Force the value of the integrator to zero
			OFF	No change to PID loop execution
Valid for inputs:		C001, C002, C003, C004,		Example (requires input configuration—see
		C005		page 3–47):
Required settings:		A071				PIDC
								PID
Notes:					L	5	4	3	2	1	PCS

•The use of [PID] and [PIDC] terminals are

optional. Use A071=01 if you want PID loop control enabled all the time.

•Do not enable/disable PID control while the motor

is running (inverter is in Run Mode).

• Do not turn ON the [PIDC] input while the motor is	See I/O specs on page 4–6.
running (inverter is in Run Mode).