Description on Dividing/Multiplier Ratio

Relation between Positional Resolution/Moving Speed and Command Dividing Multiplier Ratio

Servo driver

 

Command dividing multiplier ratio

Rotation speed: N [r/min]

 

Pulse row position

 

 

 

 

 

 

 

 

 

 

 

Pr4A

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

command

 

 

 

 

 

 

 

 

 

Pr46 x 2

 

 

Servo

 

 

 

Gear

 

Machine

 

 

 

 

 

 

 

 

D =

 

 

 

 

 

 

 

 

 

 

 

motor

 

 

 

 

Distance: P1 [P]

Pr4B

 

 

 

 

 

 

Reduction ratio: R

 

 

Traveling speed: F [PPS]

 

 

 

 

 

 

 

Encoder

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Number of encoder pulses E [P/r]

 

 

 

 

 

 

 

 

 

 

 

10000 = (phase A/B 2500 [P/r] x 4)

 

Example of driving ball screw using the servo motor

 

 

 

 

 

 

 

 

 

As an example of a machine, we describe a ball screw driving system below:

When lead of a ball screw is L [mm], actual distance of a ball screw M [mm] with respect to the distance command PI [P] is expressed with formula (1) below:

M = P1 x (D/E) x (1/R) x L

(1)

Therefore, position resolution (distance DM per command pulse) is expressed by the following formula (2):

M = (D/E) x (1/R) x L

(2)

Through transformation of formula (2), a command dividing multiplier ratio D is determined by the formula (3):

D = (M x E x R)/L

(3)

In addition, actual traveling speed V [mm/s] of a ball screw with respect to traveling speed command F [PPS] is expressed by formula (4), and the corresponding motor rotation speed N is determined by formula (5):

V = F x (D/E) x (1/R) x L

(4)

N = F x (D/E) x 60

(5)

Through transformation of formula (5), a command dividing multiplier ratio D is determined by the formula (6):

D = (N x E)/(F x 60)

(6)

<Remarks>

1.Set the positional resolution (M) at approx. 1/5 to 1/10 of the positioning accuracy (∆ε), in view of mechanical errors.

2.Set a value from 1 to 10000 to Pr46 and Pr4B.

3.You can set any value depending on numerator and denominator settings. However, if you specify an extreme dividing/multiplier ratio, we cannot guarantee proper operation of the motor. We recommend that you set the

dividing/multiplier ratio in the range of 1/50 to 20 times.

4.

2n

Decimal

 

20

1

 

21

2

 

22

4

 

23

8

 

24

16

 

25

32

 

26

64

 

27

128

 

28

256

 

29

512

 

210

1024

 

211

2048

 

212

4096

 

213

8192

 

214

16384

 

215

32768

 

216

65536

 

217

131072

178

Page 24
Image 24
Panasonic IMC80A specifications Description on Dividing/Multiplier Ratio