Electronic gear setting
Set the gear ratio between the machine gear and motor gear.
Gear ratio calculation (Pr. 420, Pr. 421)
The position resolution (travel distance per pulse Δl [mm]) is the travel distance per motor rotation Δs
[mm] and the feedback pulse of the detector.
It is determined by Pf [pulse/rev] and represented with the following formula.
The travel distance in 1 command pulse can be separately specified with a parameter and so an in-
teger 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
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.
Position control under vector control and PM sensorless vector control
Command pulse scaling
Travel distance per pulse [mm]
Travel distance in one motor rotation [mm]
Number of feedback pulses [pulse/rev] (the number of pulses after the number encoder
pulses is quadruplicated)
= Pf ×
Internal command pulse frequency [pps]
Motor rotation speed [r/min]
1 to 32767
Set the electronic gear.
Pr. 420 is the numerator and Pr. 421 is the
1 to 32767
Use it when the rotation is not smooth because the
0 to 50 s
electronic gear ratio is large (10 times or larger) and
the rotation speed is slow.
5 - 177