A.1 sigma-series ac servopack gain adjustment, A.1 σ -series ac servopack gain adjustment – Yaskawa SGDB User Manual

Page 548

SERVO ADJUSTMENT

A.1.1 Σ -Series AC SERVOPACKs and Gain Adjustment Methods

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A.1 Σ-Series AC SERVOPACK Gain Adjustment

This section gives some basic information required to adjust the servo system.

A.1.1 Σ-Series AC SERVOPACKs and Gain Adjustment Methods

Five types of Σ-Series AC SERVOPACK are available: SGD, SGDA, DR1, DR2, and the

current SGDB.
The adjustment method is basically identical for each SERVOPACK type, except that
auto-tuning is not available for some types.
The SGDB, SGDA, SGD, and DR2 SERVOPACKs allow both manual adjustment by the
conventional method of observing the machine response and automatic adjustment us-
ing the internal auto-tuning function. The DR1 SERVOPACK does not offer auto-tuning.

The main parameters changed by the customer to adjust the servo system include the
following:

• Cn-04 (Speed Loop Gain)

• Cn-05 (Speed Loop Integration Time Constant)

• Cn-17 (Torque Reference Filter Time Constant)

• Cn-1A (Position Loop Gain)

In a speed-control SERVOPACK (where speed references are applied as analog volt-
ages), the position loop is controlled by the host controller, so the position loop gain is
normally adjusted at the host controller.
If adjustment is not possible at the host controller, the same adjustment can be achieved
using Cn-03 (Speed Reference Gain), but the servomotor may not reach maximum
speed for some preset values of this parameter.

A simple block diagram of the servo system is shown below.

Servo System Block Diagram

Speed Speed

Pattern

Time

Pulse

Train

Position-control SERVO-

PACK

Speed-control SERVO-

PACK

Error

Count-

Position Control Loop

(D/A

Convert-

er)

Analog Voltage

Speed Control Loop

Speed Kv

Control

Section Ti

Current

Control

Section

Power

Con-

verter

Motor

Encoder

Using Speed-control

SERVOPACK

Host Controller (supplied by customer)

SERVO-

PACK

Using Position-control

SERVOPACK

Host Controller

(supplied by

customer)

SERVO-

PACK

Kp: Position Loop Gain

Kv: Speed Loop Gain

Ti: Integration Time Constant

Note:

A position-control SERVOPACK has no D/A converter for speed refer-

ence output. This conversion is handled by internal calculations.