4–16

Using Intelligent Input Terminals

External Signal for DC Braking

When the terminal [DB] is turned ON, the DC braking feature is enabled. Set the following parameters when the external DC braking terminal [DB] is to be used:

•A053 – DC braking delay time setting. The range is 0.1 to 5.0 seconds.•A054 – DC braking force setting. The range is 0 to 100%.

The scenarios to the right help show how DC braking works in various situations.

1.

Scenario 1 – The [FW] or [RV] terminal is

 

ON. When [DB] is ON, DC braking is

 

applied. When [DB] is OFF again, the

 

output frequency ramps to the prior level.

2.

Scenario 2 – The Run command is applied

 

from the operator keypad. When the [DB]

 

terminal is ON, DC braking is applied.

 

When the [DB] terminal is OFF again, the

 

inverter output remains OFF.

3.

Scenario 3 – The Run command is applied

 

from the operator keypad. When the [DB]

 

terminal is ON, DC braking is applied
Scenario 1

1 [FW, RV] 0

1

[DB] 0

Output frequency

t

Scenario 2

Run command 1 from operator 0

1

[DB] 0

Output frequency

t

Scenario 3

Run command 1 (from operator) 0 1

[DB] 0

after the delay time set by A053 expires.
The motor is in a free-running (coasting)

Output

delay A053

condition. When the [DB] terminal is OFF
again, the inverter output remains OFF.

frequency

t

Operations and Monitoring

Option

Terminal

Function Name

Input

 

 

Description

Code

Symbol

State

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

07

DB

External DC Braking

ON

applies DC injection braking during deceleration

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

OFF

does not apply DC injection braking during

 

 

 

 

deceleration

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Valid for inputs:

C001, C002, C003, C004,

Example (requires input configuration—see

C005

 

 

 

 

page 3–47):

 

 

 

 

Required settings:

A053, A054

 

 

 

 

 

DB

 

 

 

 

 

 

 

 

 

Notes:

 

 

 

 

L

5

4

3

2

1

PCS

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

•Do not use the [DB] input continuously or for a

long time when the DC braking force setting A054 is high (depends on the motor application).

•Do not use the [DB] feature for continuous or high

duty cycle as a holding brake. The [DB] input is

 

designed to improve stopping performance. Use a

See I/O specs on page 4–6.

mechanical brake for holding a stop position.