Справочник Пользователя для Mitsubishi Electronics FX2NC

FX Series Programmable Controllers

10-15

The PWM instruction may be used directly with an inverter to drive a motor. If this configuration
is used the following ripple circuit will be required between the PLC’s PWM output and the
inverters input terminals.

Key to component values:

R1 - 510 

Ω

 (1/2 W)

R2 - 3.3k

Ω

 (1/2 W)

R3 to R8 - 1k

Ω

 (1/4 W)

R9 - 22 

Ω

 (1/4 W)

R10 - variable dependent on configuration. In this example 1k

Ω

 (1 W)

C1 - 470 

µ

F

Note: the values of R10 and C1 are dependent on the system configuration.

It is assumed that the input impedance of the inverter is of a high order. Having established
this, the values of C1 and R10 are calculated to give 

τ

 a time result (in msec) approximately 10

times bigger than the value used for T

0

 in the PWM instruction:

τ

 = R10 (k

Ω

) ÅL C1 (

µ

F)

During this calculation the value of R10 must be vastly greater than the value of R9. In the
example, R9 is equal to 22

Ω

, where as R10 is equal to 1k

Ω

. This proportion is approximately

1:50 in favor of R10.

FX

0(S)

FX

0N

FX FX

(2C)

FX

2N(C)

Y0

+V0

24V 0V

+

E

e

R1

R2

R3

R7

R10

R

4

R

5

R

6

R

9

R

8

Inverter

C1

5V

12V

Programmable
controller

Motor

Circuit configuration for a PLC with source outputs

e

e

m

Y000

t

T

0

PWM D10 K50 Y000

X10

t

T0