Elmo SERVO AMPLIFIER DBP SERIES ユーザーズマニュアル

18

DBP - Rev 6/93

Three current feedbacks are obtained by measuring the voltage drop across

current sensing resistors or by current transformers (when using the isolation

option). These three signals are synthesized and multiplexed which result in a

single voltage signal proportional to phases currents. It is then compared to

the current command. The error is processed by the current amplifier to provide

a voltage command to the PWM section.

Current loop control is obtained by op amp U21/A (current amplifier) and R4,

C1 which form a lag-lead network for current loop. The standard amp is equipped

with R4 and C1 to get optimum current response for an average motor in this

power range. These components are mounted in solderless terminals.

Error amplifier

Current amplifier

Current feedback

CFM

x2

The amplifier is equipped with a Current Feedback Multiplier (CFM). By

turning DIP switch 2 (on the upper board of the power stage) to ON, the signal

of the current feedback is multiplied by 2 and consequently the following

changes occur:

- Current gains are multiplied by 2.

- Current monitor is divided by 2.

- Current limits are divided by 2.

- Dynamic range is improved.

- Commutation ripple is reduced.