Mitsubishi FX2N-10GM, Hardware / Programming Manual

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FX Series Positioning Controllers Program Examples 9
9-2
9.2 Setting of Parameters
Set parameters in the following order.
1) Obtain the command pulse frequency from the maximum operation speed, and change the
electronic gear on the servo amplifier if required.
2) Determine the system of units (PARA. 0).
3) Determine the pulse rate (PARA. 1) and the feed rate (PARA. 2).
However, when you select the motor system of units in PARA. 0, you do not have to set the
pulse rate and the feed rate.
4) Determine other parameters.
9.2.1 Command pulse frequency and maximum operation speed
Obtain the command pulse frequency required to rotate the servo motor HC-MF at the rated
rotation speed (3,000 r/min).
Because the command pulse frequency (f0) becomes equivalent to the feedback pulse fre-
quency at a certain rotation speed due to the characteristics of the servo motor, the following
equation is obtained.
f
0
×
= P
f
×
....................................................................................................
c
N0: Rotation speed of servo motor [r/min]
When supposing that the electronic gear ratio is "1:1" (which is the initial value of a parameter
in the servo amplifier) and obtaining "f0" from the equation
c
f
0
= P
f
×
= 8,192 [pls/rev]
×
= 409,600 [Hz]
However, because the maximum frequency of the positioning unit is 200 kHz*, you should
change the electronic gear.
When obtaining (electronic gear) from the equation
c
= P
f
× ×
= 8,192 [pls/rev]
× ×
=
Accordingly, set the parameters Nos. 3 (CMX) and 4 (CDV) in the servo amplifier to "CMX =
256, CDV = 125".
* In the FX
2N
-20GM, the maximum frequency is 100 kHz during interpolation operation.
CMX
CDV
N
0
60
N
0
60
3000[r/min]
60
CMX
CDV
CMX
CDV
N
0
60
1
f
0
3000[r/min]
60
1
200
×
10
3
[Hz]
256
125