Analog Input Responsiveness And Noise Elimination; Analog Input Time Constant (Pr.74); Analog Speed Command Input Time Constant (Pr.822, Pr.832); Analog Speed Command Input Offset Adjustment (Pr.849) - Mitsubishi Electric FR-F800 Instruction Manual

5.9.4
Analog input responsiveness and noise
elimination
The frequency command responsiveness and stability are adjustable by using the analog input (terminals 1, 2, and 4)
signal.
Pr. Name
74
Input filter time constant
T002
822
Speed setting filter 1
T003
832
Speed setting filter 2
T005
849 Analog input offset
T007 adjustment
Analog input time constant (Pr.74)
• It is effective to eliminate noise on the frequency setting circuit.
• Increase the filter time constant if steady operation cannot be performed due to noise, etc.
A larger setting results in slower response. (The time constant can be between 0 and 8, which are about 5 ms to 1 s.)
Analog speed command input time constant (Pr.822, Pr.832)
• Set the primary delay filter time constant to the external speed command (analog input command) by using Pr.822 Speed
setting filter 1.
• To change the time constant, for example, in a case where only one inverter is used to switch between more than one
motor, use Pr.832 Speed setting filter 2.
• Pr.832 Speed setting filter 2 is enabled when the RT signal is ON.
Analog speed command input offset adjustment (Pr.849)
• This is used to set a range in which the motor is stopped for prevention of incorrect motor operation in a very low speed
rotation by the analog input speed command.
• Regarding the Pr.849 Analog input offset adjustment value 100% is 0, the offset voltage is set as described below:
100% < Pr.849 ....... Positive side
100% > Pr.849 ....... Negative side
The detailed calculation of the offset voltage is as described below:
Offset voltage [V] = Voltage at the time of 100% (5 V or 10 V

It depends on the Pr.73 setting.
Frequency
command
0%
0% 100%
NOTE
• Under PID control, the analog input filter is invalid (no filter).
Parameters referred to ???????
Pr.73 Analog input selection page 306
Pr.125, C2 to C4 (bias and gain of the terminal 2 frequency setting)
Initial value
1
9999
9999
100%
Slope determined
according to Pr.125
and C2 to C4
Slope does not
change.
Speed setting
100%
signal
(10V or 5V)
200% Pr.849 setting
(T) Multi-Function Input Terminal Parameters
Setting range
The primary delay filter time constant to the analog
0 to 8 input is selectable. The higher the value, the lower
the responsiveness.
Set the primary delay filter time constant to the
0 to 5 s
external speed command (analog input command).
9999 Use the Pr.74 setting.
Second function of Pr.822 (enabled when the RT
0 to 5 s, 9999
signal is ON)
Make the analog speed input (terminal 2) have an
offset. This prevents the motor from rotating by
0 to 200%
noise to the analog input or another cause on the
speed 0 command.
)  (Pr.849 - 100)/100

page 314
Description
313
PARAMETERS
5
GROUP
T