WEIHONG NK200, Руководство пользователя

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Specialized Concentrated Focused
Operation
「
23
」
Screw Pitch
Pulse Equivalent
360
Subdivision Mechanical Deceleration Ratio
Stepping Angle

 
For instance, the selected screw lead of X-axis for a certain type of machine tool is 5mm, and the
stepping angle of stepping motor is 1.8 degree, with “10” subdivision and motor directly connected with
screw by coupling. Thus, the pulse equivalent of X-axis is:
Screw Pitch
Pulse Equivalent
360
Subdivision Mechanical Deceleration Ratio
Stepping Angle

 

Servo Motor
In general, set the default value of pulse equivalent as 0.001mm/p and calculate electronic gear ratio
(B/A). Their relationship can be shown as:
B Encoder Resolution
Electronic Gear Ratio Mechanical Deceleration Ratio
Screw Pitch
A
Pulse Equivalent
 
Namely,
B F p m
A d n

 
Electronic gear ratio (B/A): the parameter of servo driver (take YASKAWA driver as an example, B is
PN202 while A PN203). This ratio represents servo scales up or down the pulse frequency sent by CNC
system. When B is larger than A, it means scaling up and vice versa. For example, provided the pulse
frequency sent by CNC system is 100HZ, if the numerator of electronic gear ratio (B) is set as 1 while the
denominator 2, the actual running speed of servo is 50HZ. On the contrary, if the numerator is set as 2
while denominator 1, the actual running speed turns to 200HZ.
Encoder Resolution (F): needed pulse number for one circle of servo motor. Please see the servo motor
label plate and then refer to the corresponding manual to confirm its encoder resolution. A label plate of
YASKAWA SGMSH type motor is as below, and the 4th character in motor type is the serial encoder
specification, so the resolution of this motor is 2
17
, i.e. 131072.
Motor Type
：
TYPE SGMSH-1 0 A C A 2 1
Sign Spec. Remark
2
C
17-bit absolute
17-bit increment
Standard
Standard
The 4th character:
serial encoder spec.
(The 4th character)
Fig. 3-7 Name Plate of Servo Motor-encoder Resolution
For instance: (an example of YASKAWA servo) screw pitch of a certain type of machine is 5mm, with 17
bit encoder resolution, “0.0001mm/p” pulse equivalent and “1:1” deceleration ratio.
Electronic Gear Ratio
PN203
PN202
=
1
5/0.0001
17
2

=
1
5/0.0001
131072

=
3125
8192