Mitsubishi FR-A740-00023-EC, Instruction Manual

Page: 291 / 474

281
Frequency/torque setting by analog
input (terminal 1, 2, 4)
4
P
ARAME
T
E
R
S
(2) 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).
(3) Time constant of analog speed command input
(Pr. 822, Pr. 832)
⋅
Set the time constant of the primary delay filter relative to the external torque 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.
(4) 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.
(5) Offset adjustment of analog 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.
♦
Parameters referred to
♦
Pr. 73 Analog input selection Refer to page 275
Pr. 125, C2 to C4 (Bias and gain of the terminal 2 frequency setting) Refer to page 282
0% 100%
(10V or 5V)
Pr.849 setting
Frequency
command
Speed setting
signal
Slope determined
according to
Pr.125
and C2 to C4
Slope does not
change.
0% 200% 100%
* According to the Pr. 73 setting
Offset voltage =
Voltage at 100%
(5V or 10V *)
×
Pr. 849 − 100
[V]
100