Response Level Of Analog Input And Noise Elimination (Pr. 74, Pr. 822, Pr. 826, Pr. 832, Pr. 836, Pr. 849) - Mitsubishi Electric FR-A720-0.4K Instruction Manual

4.21.4 Response level of analog input and noise elimination
(Pr. 74, Pr. 822, Pr. 826, Pr. 832, Pr. 836, Pr. 849)
Response level and stability of frequency reference command and torque reference command by analog input
(terminal 1, 2, 4) signal can be adjusted.
Parameter
Name
Number
74 Input filter time constant
822 Speed setting filter 1
826 Torque setting filter 1
832 Speed setting filter 2
836 Torque setting filter 2
Analog input offset
849
adjustment
(1) Time constant of analog input (Pr. 74)
⋅ Effective for eliminating noise in the frequency setting circuit.
⋅ Increase the filter time constant if steady operation cannnot be performed due to noise.
A larger setting results in slower response (The time constant can be set between approximately 10ms to 1s with
the setting of 0 to 8).
(2) Time constant of analog speed command input (Pr. 822, Pr. 832)
⋅ Set the time constant of the primary delay filter relative to the external speed command (analog input command)
using Pr. 822 Speed setting filter 1.
Set a large time constant when you want to delay the tracking of the speed command, when the analog input
voltage fluctuates, etc.
⋅ When you want to change time constant when switching two motors with one inverter, use the Pr. 832 Speed setting
filter 2.
⋅ Pr. 832 Speed setting filter 2 is made valid when the RT signal turns on.
(3) Time constant of analog torque command input (Pr. 826, Pr. 836)
⋅ Set the time constant of the primary delay filter relative to the external torque command (analog input command)
using Pr. 826 Torque setting filter 1.
Set a large time constant value when you want to delay the tracking of the torque command, when the analog input
voltage fluctuates, etc.
⋅ When you want to change time constant when switching two motors with one inverter, etc., use Pr. 836 Torque setting
filter 2.
⋅ Pr. 836 Torque setting filter 2 is made valid when the RT signal turns on.
0%
(10V or 5V)
0% 100%
♦ Parameters referred to ♦
Pr. 73 Analog input selection
Pr. 125, C2 to C4 (Bias and gain of the terminal 2 frequency setting)
Initial Setting
Value
1
9999
9999
9999 0 to 5s, 9999
9999 0 to 5s, 9999
100% 0 to 200%
(4) Offset adjustment of analog speed command
Slope determined
according to Pr.125
and C2 to C4
Slope does not
change.
100% Speed setting
signal
200% Pr.849 setting
Refer to page 274
Frequency/torque setting by analog
Range
The primary delay filter time constant for the analog input
0 to 8
can be set. A larger setting results in slower response.
Set the time constant of the primary delay filter relative to
0 to 5s
the external speed command (analog input command).
9999 Pr. 74 used
Set the time constant of the primary delay filter relative to
0 to 5s
the external torque command (analog input command).
9999 Pr. 74 used
Second function of Pr. 822 (valid when RT terminal is on)
Second function of Pr. 826 (valid when RT terminal is on)
This function provides speed command by analog input
(terminal 2) with offset. Motor rotation due to noise, etc.
by analog input can be avoided at zero speed command.
input (Pr. 849)
⋅ When speed command by analog input is set, create the
range where the motor remains stop to prevent malfunction
at very low speed.
⋅ On the assumption that the Pr. 849 setting 100% as 0, the
offset voltage is offset as follows:
100% < Pr. 849........ positive side
100% > Pr. 849........ negative side
The offset voltage is found by the following formula.
Voltage at 100%
Offset voltage =
(5V or 10V
* According to the Pr. 73 setting
Refer to page 280
input (terminal 1, 2, 4)
Description
Pr. 849 − 100
×
100
)
*
Pr.73
page 274
Pr.73
page 277
Pr.75
page 290
Pr.821
page 103
Pr.824
page 126
Pr.825
page 126
Pr.827
page 140
Pr.831
page 103
Pr.834
page 126
Pr.835
page 126
Pr.837
page 140
Pr.850
page 194
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