76      Chapter 5  Parameter Introductions 
EV2000 Series Universal Variable Speed Drive    User Manual 
F9.21 Frequency decrease 
rate at voltage compensation 
Range:0.00~99.99Hz/s 
【10.00Hz/s】 
Trip-free operating function enables the drive to perform 
low-voltage compensation when the voltage drops or 
instantaneous under-voltage occurs. The drive can 
continue to operate without tripping by reducing its 
output frequency and feedback energy via motor. 
If F9.20 is set to 0, this function is disabled. 
If F9.20 is set to 1, this function is enabled and 
low-voltage compensation is activated. 
If F9.21 (frequency decrease rate at voltage 
compensation) is set too big, the feedback energy of 
motor will be too large and over-voltage protection might 
be activated; If F9.21 is set too small, the feedback 
energy of motor will be too small to achieve voltage 
compensation effect. So, please set F9.21 according to 
load inertia and the actual load. 
 Note: 
This function is active only for the drive of 22kW or below. 
F9.22 Restart after power failure 
Range:0. 1【0】 
F9.23 Delay time for restart after 
power failure 
Range:0.0~10.0s
【0.5s】 
F9.22 and F9.23 decide whether the drive starts 
automatically and the delay time for restart when the 
drive is switched off and then switched on in different 
control modes. 
If F9.22 is set to 0, the drive will not run automatically 
after restarted. 
If F9.22 is set to 1, when the drive is powered on after 
power failure, it will wait certain time defined by F9.23 
and then start automatically depending on the current 
control mode and the drive’s status before power failure. 
See Table 5-15. 
Table 5-15 Restarting conditions 
Setting 
of 
F9.22 
Status 
before 
power 
off 
Control modes   
Panel 
Serial 
port 
3-wire modes 
1 and 2 
2-wire modes 
1 and 2 
Without control command  With
0 
Stop 
0  0  0  0  0 
Run  0  0  0  0  0 
1 
Stop 
0  0  0  0  1 
Run  1  1  1  0  1 
 Note: 
Table 5-15 shows the drive’s action under different 
conditions. “0” means the drive enter ready status and “1” 
means the drive start operation automatically. 
When using the panel or serial port or 3-wire modes 1 and 2 
to start or stop the drive, the command signal is in pulse 
mode and there is no operating command when the drive is 
switched on. 
If there is a stopping command, the drive will stop first. 
When the function of restart after power failure is enabled, 
the drive will start on the fly after power on if it is not 
switched off totally (that is, the motor still runs and drive’s 
LED displays “P.OFF”). It will start in the starting mode 
defined in F2.00 after power on if it is switched off totally 
(LED turns off). 
For 2-wire mode 2, there is control command after 
power-on.  
5.11  Reserved (Group FA) 
FA.00~FA.11  Reserved 
5.12    Communication Parameters (Group FF) 
FF.00 Communication 
configuration 
Range:0000~1127H
【0005】 
A
 
 B
 
  C
 
  D
Baud rate
:
0: 300bps
1: 600bps
2: 1200bps
3: 2400bps
4: 4800bps
5: 9600bps
6: 19200bps
7: 38400bps
Data format
0: 1-8-1 format, no parity
1: 1-8-1 format, even parity
2: 1-8-1format, odd parity
Virtual input terminal
0: Disabled
1: Enabled
Wiring mode:
0: Cable
(
RS232/485
)
1: MODEM
(
RS232
)
 
 
Fig. 5-69  Communication parameters 
Where, 
A: thousand’s place        B: Hundred’s place 
C: Ten’s place         D: Unit’s place 
FF.00 is used to set the parameters of serial 
communication. 
Virtual terminal is used by the host PC to send 
commands. Each Bit of the data represents one terminal. 
Bit0~12 represent the status of virtual terminal X1~X8,