Mitsubishi Electric FR-A800 Series Instruction Manual page 505

 Block diagram
Terminal 1 (2, 4) input
 Analog input time constant (Pr.74)
• Use this parameter to eliminate noise on the frequency setting circuit.
• Increase the filter time constant if the operation is unstable due to noise or other factors.
If the setting is too large, response becomes slow. (The time constant can be between 0 and 8, which are about 2 ms to 1
second.)
 Analog speed command input time constant (Pr.822, Pr.832)
• Use Pr.822 Speed setting filter 1 to set the primary delay filter time constant to the external speed command (analog
input command). Increase the setting of the time constant to allow delays in follow-up of the speed command or when the
analog input voltage is unstable.
• Use Pr.832 Speed setting filter 2 to change the time constant to use one inverter to switch operation between two or more
motors.
• Pr.832 Speed setting filter 2 is enabled when the RT signal is ON.
 Analog torque command input time constant (Pr.826, Pr.836)
• Use Pr.826 Torque setting filter 1 to set the primary delay filter time constant to the external torque command (analog
input command). Increase the setting of the time constant to allow delays in follow-up of the torque command or when the
analog input voltage is unstable.
• Use Pr.836 Torque setting filter 2 to change the time constant to use one inverter to switch operation between two or
more motors.
• Pr.836 Torque setting filter 2 is enabled when the RT signal is ON.
 Analog speed command input offset adjustment (Pr.849)
• Use this parameter to set a range in which the motor is stopped for prevention of incorrect motor operation in a very low
speed rotation when the speed command is an analog input.
• The voltage range is offset according to the setting in Pr.849 Analog input offset adjustment, assuming that 100%
corresponds to zero.
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
504
5. PARAMETERS
5.12 (T) Multi-function input terminal parameters
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RT-OFF
RT-ON
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Pr.74
Pr.822 = 9999
Pr.822
Pr.822 9999
Pr.74
Pr.826 = 9999
Pr.826
Pr.826 9999
Pr.832 = 9999
Pr.832
Pr.832 9999
Pr.836 = 9999
Pr.836
Pr.836 9999
*1
) × (Pr.849 - 100) / 100
Speed command
Torque command