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Hitachi L100 300 User Manual

Pid control.
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HITACHI INVERTER
SJ/L100/300 SERIES

PID CONTROL

USERS' GUIDE
After reading this manual, keep it for future reference
Hitachi America, Ltd.
HAL100PID

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   Summary of Contents for Hitachi L100 300

  • Page 1: Pid Control

    HITACHI INVERTER SJ/L100/300 SERIES PID CONTROL USERS’ GUIDE After reading this manual, keep it for future reference Hitachi America, Ltd. HAL100PID...

  • Page 2: Table Of Contents

    CONTENTS 1. OVERVIEW 2. PID CONTROL ON SJ100/L100 INVERTERS 2-1 PID Control (1) P : Proportional Control (2) I : Integral Control (3) D : Differential Control (4) PID Control 2-2 PID Gain Adjustments & Control Characteristics 3. HOW TO USE 3-1 Structure &...

  • Page 3: Overview

    1. OVERVIEW SJ100/L100 series inverters have an integrated PID control function as standard. They can be used for controls, such as constant flow control for fan & pump applications, and they have the following features. Target signal can be given not only by the digital operator but also by an external digital signal, which can be set to 16 different targets.

  • Page 4: P : Proportional Control

    SJ100/L100 series inverters have integrated PID control, which is indicated by the dotted line in Fig. 2-1. You can use PID control by setting a target value and providing a feedback signal. The example in Fig. 2-2 shows a connection diagram for ventilation flow control in a fan application. SJ100/ Target L100...

  • Page 5: I: Integral Control

    (2) I: Integral Control This is a control to correct the output frequency by integrating the deviation. In the case of proportional adjustment, a large deviation will result in a large output frequency adjustment, but if the deviation is small, then the resulting adjustment of output frequency will also be small. However, you cannot make the deviation zero.

  • Page 6: Pid Gain Adjustments & Control Characteristics

    2-2 PID Gain Adjustments & Control Characteristics The optimal gain factors of PID vary from condition to condition, and from system to system. That means it is necessary to set those parameters by taking into account the individual control characteristics of your particular system.

  • Page 7: How To Use

    3. HOW TO USE 3-1 Structure & Parameters (1) Control Mode Integrated operator A71 : 00 / 01 DOP, DRW SJ100/L100 series inverters feature the following two control modes: Frequency control mode PID control mode These can be selected by “PID function selection (A71)”. Frequency control mode is the typical control mode of standard frequency inverters which enables you to give a frequency command to the inverter from either the operator panel, or by analog voltage or current, or by 4 bit digital command from the control terminals.

  • Page 8: Deviation Calculation

    (3) Deviation Calculation Every calculation in PID control in the SJ100/L100 is based on “%” so that it can be used with various applications and units of measure, such as pressure (N/m and so on. For example, comparing target value and feedback value is based on % of target and % of feedback full scale value.

  • Page 9: Scale Conversion

    20mA 100% (a) A13 = A14 = 100% A11 = A12 = 100% Fig. 3-3 Setting Active Range : Example 2 As you can see from Fig 3-3, if you set parameters A11 and A12 other than “0”, you should set the target value inside the valid range of the vertical axis.

  • Page 10

    3-2 Summary of Parameters for PID Control On the SJ100/L100 series inverters, the same function numbers are used for both frequency control mode and PID control mode. The function name for each function is based on frequency control mode, which is normally used for general application. Therefore, some functions have misleading explanations in the instruction manual.

  • Page 11: Examples Of Set Up

    3-3 Example of Set Up (1) Parameter Set Up under Frequency Control Mode Before driving the system in PID mode, you set up each required parameter under frequency control mode. Pay particular attention to the following items. Acceleration ramp and Deceleration ramp The output of the PID calculation (refer to Fig.

  • Page 12: Scale Conversion Factor Setting

    (3) Scale Conversion Factor Setting Set this factor according to your application, e.g. flow, pressure, temperature and so on. For a detailed explanation, please refer to item (6) on page 9. (4) Target Input by Digital Input Signal Please refer to the following when changing the target with the digital input signal (4 bit max.). (a) Input terminal assignment L100 series inverters have five intelligent input terminals.

  • Page 13: Example Of Each Gain Adjustment (kp & Ti)

    3-4 Example of Each Gain Adjustment (K Check the response of feedback signal or the output frequency of the inverter when making a step change in the target. (Please refer to Fig. 2-4) Use an oscilloscope or other measuring equipment to observe the waveform of the feedback value or output frequency of the inverter (frequency monitor).

  • Page 14: Examples Of Actual Application

    4. EXAMPLE OF ACTUAL APPLICATION You can find in this chapter some typical setting examples for actual applications. 4-1 Constant Flow Control L100/ SJ100 Target 4 bit digital signal Motor Fig. 4-1 Example of Constant Flow Control In this case (targets are 150m 300m /min), the settings would be as follows: Function Number...

  • Page 15: Constant Temperature Control

    4-2 Constant Temperature Control In the case of constant flow control shown in the previous section, output frequency of the inverter increases if the feedback value is smaller than target value, and output frequency of the inverter decreases if the feedback value is bigger than the target value. However, in the case of constant temperature control, this is the opposite.

  • Page 16: Index

    5. INDEX - A - acceleration ramp AVR function - C - control mode 7, 10 - D - damped oscillation deceleration ramp deviation 3, 8 differential control differential gain (Kd : D-gain) divergence - F - feedback feedback origin input frequency control mode - G - gain adjustment...

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