PID Loop Operation

L100 Inverter

4–27

In standard operation, the inverter uses a reference source selected by parameter A01 for the output frequency, which may be a fixed value (F01), a variable set by the front panel potentiometer, or value from an analog input (voltage or current). To enable PID opera- tion, set A71 = 01. This causes the inverter to calculate the target frequency, or setpoint.

A calculated target frequency can have a lot of advantages. It lets the inverter adjust the motor speed to optimize some other process of interest, while saving energy as well. Refer to the figure below. The motor has some eventual effect on a process of interest. To control the external process, the inverter must monitor the process variable. This requires wiring a sensor to either the analog input terminal O (voltage) or terminal OI (current).

Setpoint	∑	Error	PID	Freq.	Motor	External
SP	∑		Calculation	Inverter	Motor	Process
SP			Calculation			Process
	PV
					Process Variable (PV)		Sensor
							Sensor

When enabled, the PID loop calculates the ideal output frequency to minimize the loop error. This means we no longer command the inverter to run at a particular frequency, but we specify the ideal value for the process variable. That ideal value is called the setpoint, and is specified in the units of the external process variable. For a pump application it may be gallons/minute, or it could be air velocity or temperature for an HVAC unit. Parameter A75 is a scale factor that relates the external process variable units to motor frequency. The figure below is a more detailed diagram of the PID function.

Setpoint

Standard

(Target)

setting

Scale factor

F01

Frequency

reciprocal

Multi-speed

source select

1/A75

A01

settings

A20 to A35

Potentiometer

Error

Scale factor

A75

P gain

A72

F01

Frequency

Operations and

on keypad

SP ∑

V/I input

select

[AT]

Process Variable

Voltage

(Feedback)

I gain A73

D gain A74

∑

setting

Monitoring

O	Analog input scaling
A GND	A12
L	A11
	A11
	A15	A13	A14
OI	A76
Current	A76
Current	PID V/I
	PID V/I
	input select

Scale factor

A75

Monitor

D04

L100 specifications

The Hitachi L100 series is a versatile range of variable frequency drives (VFDs) designed to enhance performance in various industrial applications. Known for their reliability and efficiency, these drives are widely used in motors for pumps, fans, compressors, and conveyors.

One of the main features of the Hitachi L100 is its impressive control capabilities. The drive supports both scalar and vector control modes, allowing for precise speed and torque management. This flexibility ensures optimal motor performance across different load conditions. Additionally, the L100 series offers an impressive speed range, which can accommodate a wide variety of applications, from low-speed to high-speed requirements.

The L100 is equipped with built-in functionality for energy saving. By utilizing advanced control algorithms and auto-tuning features, the drive optimizes energy consumption, reducing operational costs and contributing to improved overall system efficiency. The energy-saving mode is particularly beneficial in applications where load conditions frequently change.

Another hallmark of the Hitachi L100 is its robust communication capabilities. The drive supports various communication protocols including Modbus and Ethernet, making it easy to integrate into existing control systems. This connectivity allows for real-time monitoring and diagnostics, which aids in predictive maintenance and minimizes downtime.

In terms of user-friendliness, the L100 series includes a clear, intuitive keypad that simplifies programming and operation. The drive also features a wide range of customizable parameters, enabling users to easily tailor the settings to suit specific application requirements. Additionally, the inclusion of a customizable PID controller allows users to refine process control automatically.

Safety is a priority in the design of the Hitachi L100. The drive comes with various built-in safety features such as overvoltage, overload, and short-circuit protection, ensuring reliable operation in challenging environments. Furthermore, it complies with global safety standards, making it suitable for international applications.

Lastly, the L100's compact design ensures easy installation and minimizes the space required in control cabinets. This is especially advantageous in facilities where space is at a premium. Overall, the Hitachi L100 series represents a combination of advanced technology, user-friendly features, and reliable performance, making it a popular choice for industrial automation solutions.

Hitachi L100 instruction manual PID Loop Operation

Models: L100

L100 Inverter

PID Loop Operation

L100 specifications