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PID Second Stage Output

The inverter has a built-in PID loop feature for two-stage control, useful for certain applications such as building ventilation or heating and cooling (HVAC). In an ideal control environment, a single PID loop controller (stage) would be adequate. However, in certain conditions, the maximum output energy from the first stage is not enough to maintain the Process Variable (PV) at or near the Setpoint (SP). And, the output of the first stage is in saturation. A simple solution is to add a second stage, which puts an additional and constant amount of energy into the system under control. When size properly, the boost from the second stage brings the PV toward the desired range, allowing the first stage PID control to return to its linear range of operation.

The two-stage method of control has some advantages for particular applications.

ξThe second stage is only ON in adverse conditions, so there is an energy savings during normal conditions.

ξSince the second stage is simple ON/OFF control, it is less expensive to add than just duplicating the first stage.

ξAt powerup, the boost provided by the second stage helps the process variable reach the desired setpoint sooner than it would if the first stage acted alone.

ξEven though the second stage is simple ON/OFF control, when it is an inverter you can still adjust the output frequency to vary the boost it provides.

Refer to the example diagram below. Its two stages of control are defined as follows:

ξStage 1 - Inverter #1 operating in PID loop mode, with motor driving a fan

ξStage 2 - Inverter #2 operating as an ON/OFF controller, with motor driving a fan

Stage #1 provides the ventilation needs in a building most of the time. On some days, there is a change in the building’s air volume because large warehouse doors are open. In that situation, Stage #1 alone cannot maintain the desired air flow (PV sags under SP). Inverter #1 senses the low PV and its PID Second Stage Output at [FBV] terminal turns ON. This gives a Run FWD command to Inverter #2 to provide the additional air flow.

Monitoring

Operationsand

Monitoring

Operationsand

 

 

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Hitachi CP-X200 instruction manual 47, PID Second Stage Output
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CP-X200 specifications

The Hitachi CP-X200 is a versatile and robust projector designed to cater to the needs of educational and business environments. It combines affordability with high-quality performance, making it an attractive option for various presentations and multimedia applications.

At the heart of the CP-X200 is its high brightness capability, with a lumen output of 3,000 ANSI lumens. This feature enables the projector to deliver clear and vibrant images even in well-lit rooms. The resolution of XGA (1024 x 768 pixels) ensures that text and graphics are sharp, making it suitable for everything from classroom lectures to corporate presentations.

One of the standout characteristics of the Hitachi CP-X200 is its advanced lamp technology. The projector uses a long-lasting lamp that can provide up to 5,000 hours of usage in standard mode, allowing for extended intervals between lamp replacements. Additionally, the ECO mode can further enhance the lamp life, extending its longevity while reducing energy consumption.

The CP-X200 is equipped with a variety of connectivity options, including HDMI, VGA, and composite inputs, allowing users to easily connect it to various devices such as laptops, DVD players, and other multimedia systems. The inclusion of USB and RS-232 interfaces ensures compatibility with different control systems, making it a flexible choice for diverse setups.

Another significant feature is the projector's built-in 10-watt speaker, which provides decent audio output, eliminating the need for external speakers in smaller venues. The speaker system enhances presentations, ensuring that audio and visuals are cohesive, promoting better audience engagement.

Portability is another key aspect of the Hitachi CP-X200, which weighs just around 3.5 kg (approximately 7.7 lbs), allowing for easy transport between locations. Its compact design makes it suitable for both fixed installations and mobile use, catering to professionals who require a projector that adapts to various environments.

The user-friendly interface and robust remote control enhance the projector's operability, providing easy access to essential functions. Additionally, features such as auto keystone correction adjust the image to maintain consistent quality even when the projector is not perfectly aligned with the screen.

In summary, the Hitachi CP-X200 is a feature-rich projector that embodies reliability, performance, and ease of use. Its combination of high brightness, various connectivity options, long lamp life, portability, and integrated audio makes it an excellent choice for education and business professionals seeking a dependable presentation solution.
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