Interpret time-related conceptual terms in frequency converters

       Interpret time-related conceptual terms in frequency converters
　　There are many concepts and terms related to time in various inverter manuals, and their definitions are now interpreted as follows.
　　Acceleration time: The time for the frequency to accelerate from 0Hz to 50Hz when the motor starts is called the acceleration time. When the end frequency of starting is less than 50Hz, the actual required acceleration time will be shortened accordingly.
　　Deceleration time: The time for the frequency to decrease from 50Hz to 0Hz when the motor stops is called the deceleration time. When the operating frequency at the moment of deceleration and shutdown is less than 50Hz, the actual required deceleration time will be shortened accordingly.
　　Starting DC braking time: Before starting, the inverter outputs a DC voltage to brake the motor. The duration of this braking voltage is called the starting DC braking time. After the DC braking time expires, the motor starts immediately.
　　Stop DC braking time: the duration of the output DC braking voltage during the stop process of the inverter.
　　Dead time of forward and reverse rotation: the waiting time after the inverter output frequency drops to 0 during the process of switching from the current running direction to the opposite running direction after receiving the reverse running command while the inverter is running.
　　Fault test recovery waiting time: When a fault occurs during operation, the inverter stops output. After a period of waiting time, the inverter automatically resets the fault and continues to run. This period of time is the fault recovery waiting time.
　　JOG acceleration time: the acceleration time during jog operation.
　　JOG deceleration time: the deceleration time during jog operation.
　　Acceleration time 2/Deceleration time 2: Determined according to the program or selected by the multi-function terminal, it is used for the acceleration and deceleration time during multi-speed operation. Acceleration time 3/deceleration time 3, etc. are defined similarly.
　　Instantaneous power failure restart waiting time: the minimum time allowed to restart after instantaneous power failure. During this time, the residual voltage after the motor is powered off disappears.
　　Acceleration for a long time: Some inverters, such as Fuji G11S inverter, can automatically extend the acceleration time for the acceleration process of more than 60 seconds. When this function setting is valid, the acceleration time is automatically extended to 3 times the set acceleration time, in order to prevent the inverter from tripping due to overcurrent rising of the internal temperature.
　　Integral time: "I" among the three closed-loop control parameters of PID. Can affect the size of the PID control effect. If the integration time is long, the response to the feedback signal is slow, and the control ability to external disturbances becomes poor; if the integration time is small, the response speed to the feedback signal is fast, but if it is too small, oscillation will occur.
　　Differential time: "D" among the three closed-loop control parameters of PID. When the differential time is large, the oscillation can be attenuated quickly, but when it is too large, it will cause oscillation; when the differential time is small, the damping effect is reduced.
　　Delay time of adding pump: In a multi-pump constant pressure water supply system, if the main pump has been started, it must be delayed for a period of time to start other main pumps to ensure the stability of the pressure of the water supply system. The delay time here is the delay time of adding pump. time.
　　Pump reduction delay time: In a multi-pump constant pressure water supply system, if a certain main pump has been shut down, it must be delayed for a period of time to shut down other main pumps to ensure the stability of the water supply system pressure. The delay time here is Decrease pump delay time.
　　Sleep waiting time: In the multi-pump constant pressure water supply system, when the output frequency of the inverter reaches or is less than the sleep frequency and the feedback pressure is higher than the sleep value of the inverter, and continues to run for a period of time for confirmation, the motor stops and enters the sleep state. The so-called continuous running confirmation time here is the sleep waiting time.
　　Replacement gap time: The gap time when the motor switches from variable frequency operation to power frequency operation is called the replacement gap time.
　　Feedback sampling period: the time period during which the inverter captures the feedback signal of the sensor. It can be set according to the system time constant.
　　Timing replacement time: when the inverter is dragged for more than one time, the time for multiple motors to work in turn. Each motor can be guaranteed to have roughly the same working time. For example, the inverter drives a total of 3 motors, and the 3 motors control the same object, and the time for regular replacement is 24 hours. At present, when the 1# and 2# motors are actually running, after 24 hours of operation, the 3# motor will start, and the 1# and 2# motors with a longer running time will stop running. Obviously, this timing change mode is conditional, that is, the system allows the motor to take a rest.
　　Timer: The concept of a timer is very straightforward. It is triggered by an external terminal in the inverter. It starts timing from the time it receives an external trigger signal. After the timer expires, a valid pulse with a width of several hundred ms is output at the corresponding OC terminal. Signal. The so-called "OC terminal output" is the open-collector output, which is widely used in electronic technology. I won't go into details.
　　Electromagnetic switch switching delay time: refers to the delay time of electromagnetic switch action when the motor switches from power frequency to variable frequency or from variable frequency to power frequency. It can prevent the output end of the inverter from being short-circuited with the power supply due to the delay of the electromagnetic switch action.