Mitsubishi Electric FR-F720-00046 Instruction Manual page 106

(2) Deceleration time setting (Pr.8, Pr.20)
⋅ Use Pr. 8 Deceleration time to set the deceleration time required to reach 0Hz from Pr. 20 Acceleration/deceleration
reference frequency.
⋅ Set the deceleration time according to the following formula.
Deceleration
=
Maximum operating
time setting
frequency - Pr. 10
Example) How to find the setting value for Pr.8 when decreasing the
output frequency from the maximum frequency of 50Hz in 10s
with Pr.20 = 120Hz and Pr.10 = 3Hz.
(3) Change the setting range and increments of the acceleration/deceleration time (Pr.21)
⋅ Use Pr. 21 to set the acceleration/deceleration time and minimum setting range.
Setting 0 (initial value)......................0 to 3600s (minimum setting increments 0.1s)
" "
Setting 1 ...........................................0 to 360s (minimum setting increments 0.01s)
" "
CAUTION
⋅ Changing the Pr. 21 setting changes the acceleration/deceleration time setting (Pr. 7, Pr. 8, Pr. 16, Pr. 44, Pr. 45).
(The Pr. 611 Acceleration time at a restart setting is not affected.)
<Example>
When Pr. 21 = "0", setting "5.0" s in Pr. 7 and "1" in Pr. 21 automatically changes the Pr. 7 setting to "0.5" s.
(4) Set multiple acceleration/deceleration time (RT signal, Pr.44, Pr.45)
⋅ Pr. 44 and Pr. 45 are valid when the RT signal is on.
⋅ When "9999" is set in Pr. 45, the deceleration time becomes equal to the acceleration time (Pr. 44).
CAUTION
⋅ In S-shaped acceleration/deceleration pattern A (refer to page 99), the set time is the period required to reach the base
frequency set in Pr.3 Base frequency.
⋅ Acceleration/deceleration time formula when the set frequency is the base frequency or higher
4 T
× 2
t =
× f
2
9
(Pr.3)
⋅ Guideline for acceleration/deceleration time when Pr. 3 Base frequency = 60Hz (0Hz to set frequency)
Frequency setting (Hz)
Acceleration/
deceleration time (s)
⋅ The RT signal can be assigned to the input terminal using any of Pr. 178 to Pr. 189 (Input terminal function selection). Changing
the terminal assignment using Pr. 178 to Pr. 189 (input terminal function selection) may affect the other functions. Make setting
after confirming the function of each terminal.
REMARKS
⋅ The RT signal acts as the second function selection signal and makes the other second function valid. (Refer to page 119)
⋅ The RT signal is assigned to the RT terminal in the default setting. By setting "3" to any of Pr. 178 to Pr. 189 (Input terminal
function selection), you can assign the RT signal to the other terminal.
⋅ If the Pr. 20 setting is changed, the Pr. 125 and Pr. 126 (frequency setting signal gain frequency) settings do not change. Set Pr.
125 and Pr. 126 to adjust the gains.
⋅ When the Pr. 7, Pr. 8, Pr. 44 and Pr. 45 settings are 0.03s or less, the acceleration/deceleration time is 0.04s. At that time, set
Pr. 20 to "120Hz" or less.
⋅ If the acceleration/deceleration time is set, the actual motor acceleration/deceleration time cannot be made shorter than the
shortest acceleration/deceleration time determined by the mechanical system J (moment of inertia) and motor torque.
♦ Parameters referred to ♦
Pr. 3 Base frequency Refer to page 84
Pr. 10 DC injection brake operation frequency
Pr. 29 Acceleration/deceleration pattern selection
Pr. 125, Pr. 126 (Frequency setting gain frequency)
Pr. 178 to Pr.189 (Input terminal function selection)
Pr.20
Deceleration time from maximum
×
operating frequency to stop.
5
T: Acceleration/deceleration time setting value(s)
T
+
f : Set frequency(Hz)
9
60
5 5
15 15
Refer to page 106
Refer to page 99
Refer to page 168
Refer to page 116
Setting of acceleration/deceleration time
and acceleration/deceleration pattern
120Hz
Pr.8 =
50Hz - 3Hz
120 200 400
12 27 102
35 82 305
×
10s 25.5s
4
97