Frequency signal processing method most commonly used in frequency converter

by:V&T Technologies     2019-11-15
For normal operation, the inverter must have two basic conditions, namely frequency signal and Operation signal. Let's talk about the first condition, the frequency signal of the inverter. The purpose of using the inverter is to change the speed of the motor by changing the output frequency of the inverter. How to adjust the output frequency of the inverter? The key is to change the frequency signal provided by the inverter. This signal is called 'frequency given signal '. The frequency signal source has the following ways. First, the operator panel is given. The operation panel is the simplest frequency setting mode of the inverter. The user can directly change the set rate of the inverter through the potentiometer, numeric keys or ascending keys and descending keys on the inverter operation panel. The biggest advantage of the operation panel is that the operation is simple and convenient, and it has monitoring function, that is, it can display current, voltage, speed, etc. when the inverter is running in real time. If the number of or up keys is selected and the DROP key is given, the accuracy and resolution are very high because the number is the most given. If the potentiometer on the selector is selected, it belongs to a given analog quantity with slightly lower accuracy, but it is very practical because no additional wiring, such as analog input of an external potentiometer, is required. Second, the external potentiometer gives the frequency to be adjusted by the potentiometer input from the outside of the converter. Third, the multi-function input terminal, the multi-function input terminal of the inverter is used to change the set frequency value of the inverter. The terminal can be connected to a button or output point of a plc or relay. At the function input of the inverter, set two or more terminals for frequency setting. Commonly used are: 1. Forward and reverse given: select two of the multi-function input terminals to make them 'forward' terminals and 'reverse' terminals after the function is preset, as shown in the following figure. 2, multi-speed given: multiple function input terminals, through the function preset, make it a multi-speed control terminal, through different combinations of several terminals, you can get different speeds. Four, the analog quantity is given, provided by RS485 interface or PLC provided by inverter. The analog signal is given by the analog terminal of the converter, and the output frequency of the converter is changed by adjusting the size of the analog signal. 1. The voltage signal is given: in most cases, the required voltage signal is obtained by externally accessing the potentiometer and using the power supply provided in the converter. Most converters usually have two or more voltage signal inputs. The given voltage range is: 0 ~ 10 V, 0 ~ 10 V, 0 ~ 5 V, 0 ~ 5 V, etc. 2. Give the current signal: the given range is 0-20mA and 4-20mA. 3, given the pulse. The given frequency signal is a pulse signal.
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