4–26

Analog and Digital Monitor Output

Current Monitor, PWM Signal – (C23 = 01) – The [FM] output duty cycle varies with the inverter output current to the motor. The signal period T is fixed at 4 ms, and the amplitude is fixed at 10 VDC. The signal on [FM] reaches full scale when the inverter output current reaches 200% of the rated inverter current. You can scale the duty cycle by a scale factor setting with parameter B81. The accuracy of the current reading is given by the equation:

Imc---------------------– Im ⋅ 100 ≤ ± 20%

Im = Inverter output current (measured)

Imc = Monitor display current

Ir

Ir = Inverter rated current

 

NOTE: The monitor display accuracy (normally ± 20%, depending on the connected motor’s characteristics) can be improved by the adjustment of parameter B32. If precise current measurement is necessary, use the moving-coil type ammeter between the inverter and the motor.

TIP: When using the analog meter for monitoring, adjust the meter so it has a zero reading when the [FM] output is zero. Then use scale factor B81 to adjust the [FM] output so the maximum frequency in the inverter corresponds to a full-scale reading on the meter.

PWM Smoothing Circuit – You may need to smooth the PWM signal, converting it to a relatively stable DC analog voltage which represents the [FM] output value. To do this, use the circuit shown to the right. Note the output impedance of the circuit is at least 82k Ohms, so the monitoring device needs an input impedance of 1 Meg. Ohms or greater. Otherwise, the impedance of the smoothing circuit will cause a non-linearity in the reading.

H

O OI

L

FM CM2 12 11

 

 

 

–

+

 

 

 

 

82kΩ

 

 

 

 

+

 

 

33kΩ

 

+ 1∝ F

Volts

 

 

 

–

 

See I/O specs on page 4–5.

Operations and Monitoring

Frequency Monitor, FM Signal – (C23 = 02) – The [FM] output frequency varies with the inverter output frequency. The maximum frequency of [FM] is 3.6 kHz, or 10 times the inverter maximum frequency. The signal on [FM] reaches the maximum frequency when the inverter outputs the maximum frequency. You can scale its relationship to the inverter output with the scale factor setting with parameter B86.

Frequency modulation (digital)

50% fixed duty cycle

[FM]

T

=

1

------------------------------

 

 

 

Output value

10V

 

 

 

0 V

 

 

 

 

T

 

time

 

 

 

C23 = 02 Inverter output frequency

B86 Freq. scale factor

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Image 117
Hitachi L100 instruction manual Analog and Digital Monitor Output, + 1∝ F
Page 116 Page 118

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.
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