Instruction manual

107
4
PARAMETERS
2)Pr. 254 " analog polarity reversible lower limit "
The lower limit of the analog voltage value applied across terminals 2-5 can be set.
(This setting will prevent a reversible operation (rotation) when the analog voltage
applied across terminals 2-5 drops.)
Terminal 2 input voltage is 0V = 0% and 5V (10V) = 100%.
Note: Set "10" or "11" in Pr. 73 and any value in Pr. 254 to make this function valid.
<Output frequency under the following conditions>
 When analog voltage value < Pr. 254 setting (%), output frequency of inverter is 0Hz.
4.2.29 Input filter time constant (Pr. 74)
Pr. 74 "filter time constant"
You can set the input section's internal filter constant for an external voltage or current
frequency setting signal.
• Effective for eliminating noise in the frequency setting circuit.
• Increase the filter time constant if steady operation cannot be performed due to noise.
A larger setting results in slower response. (The time constant can be set between
approximately 1ms to 1s with the setting of 0 to 8. A larger setting results in a larger
filter time constant.)
 When Pr. 254 setting (%) ≤ analog
voltage value (%)
≤ Pr. 254 setting (%) +
5.0%, output frequency is same as
when Pr. 254 setting (%) + 5.0%
Ex.) When setting "10"or "11" in Pr. 73,
0Hz and 2.5V in Pr. 902, and 60Hz
and 5V in Pr. 903 to give a forward
rotation command
REMARKS
A reversible operation can not be performed during PID control.
Note: If "801" is set in Pr. 77, be sure to reset it to the original setting.
WARNING
Do not design the wiring and facility which will make the voltage lower than
the Pr. 902 setting suddenly.
Doing so can cause the inverter to provide reverse rotation output if the
analog signal wiring is disconnected or the speed command analog signal
turns to 0V, resulting in hazardous conditions.
Parameter
Number
Factory
Setting
Setting
Range
74 1 0 to 8
Output frequency[Hz]
Output frequency[Hz]
Input voltage
(Terminal 2)
[V]
5V
(10V)
100%
Reverse
rotation
Forward
rotation
0Hz
2.5V
(5V)
50%
Use Pr. 73
Pr. 903
Pr. 902
0V
(0V)
0%
Pr. 254
Pr. 254+5.0%
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