Electronic Gear Settings - Mitsubishi Electric FR-A800 Series Instruction Manual

NOTE
• When the power is turned OFF during the reset process, the cumulative pulse monitor value and the cumulative pulse overflow
times are not stored in the EEPROM.
• For storing the cumulative pulse monitor value and the cumulative pulse overflow times in the EEPROM at power OFF, connect
R1/L11 with P/+, and S1/L21 with N/- so that the control power is retained. When connecting the FR-HC2 high power factor
converter or the converter unit (FR-CC2), assign the FR-HC2/FR-CC2 instantaneous power failure detection (X11) signal to
an input terminal to input the IPF signal from the FR-HC2/FR-CC2 to the terminal for X11 signal.
Parameters referred to
Pr.52 Operation panel main monitor
5.5.9
PM PM PM
Vector Vector Vector
Set the gear ratio between the machine gear and motor gear.
Pr.
Command pulse scaling factor
420
numerator (electronic gear
B001
numerator)
Command pulse multiplication
421
denominator (electronic gear
B002
denominator)
424 Position command acceleration/
B005 deceleration time constant
 Gear ratio calculation (Pr.420, Pr.421)
The position resolution (travel distance per pulse Δ [mm]) is the travel distance per motor rotation Δs [mm] and the feedback
pulse Pf [pulses/rev] of the detector.
Δ
The travel distance in 1 command pulse can be separately specified with a parameter and so an integer can be set as the travel
distance in 1 command pulse.
The following formula shows the relationship between the motor speed and internal command pulse frequency.
NOTE
• Set the electronic gear ratio in the range of 1/50 to 20. Note that, if the setting value is too small, the speed command will also
be too small; while if it is too large, the speed ripple will be too large.
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Electronic gear settings

Name
Δ : Travel distance per pulse [mm]
Δs
Δs: Travel distance in one motor rotation [mm]
＝
Pf
pf: Number of feedback pulses [pulse/rev] (the number of pulses after the number encoder
pulses is quadruplicated)
Pr.420
fo × = Pf ×
Pr.421
search engine
Setting
Initial value
range
1 1 to 32767
Set the electronic gear.
Pr.420 is the numerator and Pr.421 is the denominator.
1 1 to 32767
Use it when the rotation is not smooth because the
0 s 0 to 50 s electronic gear ratio is large (10 times or larger) and the
rotation speed is slow.
Δs Pr.420
＝
Δ ×
Pf Pr.421
No
fo: internal command pulse frequency [pulses/s]
No: motor rotation speed [r/min]
60
5.5 Position control under vector control and PM sensorless vector control
Description
5. PARAMETERS
1
2
3
4
5
6
7
8
9
10
325