Electronic Gear Setting - Mitsubishi Electric 800 Series Instruction Manual

Position control under vector control
5.5.8

Electronic gear setting

Set the gear ratio between the machine gear and motor gear.
Pr. Name
Command pulse scaling factor
420
numerator (electronic gear
B001
numerator)
Command pulse multiplication
421
denominator (electronic gear
B002
denominator)
Position command
424
acceleration/deceleration time
B005
constant
Gear ratio calculation (Pr.420, Pr.421)
• The position resolution (travel distance per pulse 
feedback pulse of the detector.
It is determined by Pf [pulse/rev] and represented with the following formula.
s
=

Pf
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.
s
Pr.420

 =
Pf Pr.421
The following formula shows the relationship between the motor speed and internal command pulse frequency.
Pr.420
 = Pf 
fo
Pr.421
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.
232
PARAMETERS
Initial value
1
1
0 s
 : Travel distance per pulse [mm]
s: Travel distance in one motor rotation [mm]
pf: Number of feedback pulses [pulse/rev] (the number of pulses after the number encoder pulses is
quadruplicated)
No fo: internal command pulse frequency [pulses/s]
60
No: motor rotation speed [r/min]
Vector Vector Vector
Setting range
1 to 32767
Set the electronic gear.
Pr.420 is the numerator and Pr.421 is the
denominator.
1 to 32767
Use it when the rotation is not smooth because
0 to 50 s the electronic gear ratio is large (10 times or
larger) and the rotation speed is slow.
[mm]) is the travel distance per motor rotation s [mm] and the
Description