Operation; Start, Stop And Reset Commands; Soft Start Methods - Emerson Digistart IS1x0043B series User Manual

Safety Rating Mechanical
Information Data Installation
7.

Operation

7.1

Start, stop and reset commands

The soft starter can be controlled in three ways:
 using the buttons on the keypad
 via remote inputs
 via a serial communication link
The LCL/RMT button controls whether the Digistart IS will respond to local control (via the keypad) or remote control (via the remote
inputs).
 The Local LED on the keypad is on when the soft starter is in local control mode and off when the soft starter is in remote
control mode.
 The Remote LED on the Digistart IS is on when the soft starter is in Remote mode and off when in Local mode. The
Remote LED is located on the main body of the starter (behind the keypad) and is only visible if the keypad is remotely
mounted.
Control via the serial communication network is always enabled in local control mode, and can be enabled or disabled in remote
control mode (see Pr 3O). Control via the serial communication network requires an optional communication module.
The STOP button on the keypad is always enabled.
To reset a trip on the soft starter, press the RESET button on the keypad or activate the Reset remote input.
Adaptive Control, Jog, Brake and PowerThrough functions are not supported with inside delta (six-wire) operation. See
NOTE
Inside Delta Operation on page 43.
7.2

Soft start methods

Soft starters offer a variety of methods to control motor starting. Each soft start method uses a different primary control parameter.
Table 7-1 Soft start methods
Soft Start Method
Timed Voltage Ramp
Constant Current
Torque Control
Adaptive Control
Best results are obtained by selecting the soft start method that directly controls the parameter of most importance for the
application. Typically soft starters are used to limit motor start current or control load acceleration and/or deceleration.
The Digistart IS offers Constant Current or Adaptive Control. Use Pr 2A to select the soft start method.
Table 7-2 Control functions of soft start methods
To Control
Motor Start Current
Motor/Load Acceleration
To soft start the motor, press the START button on the keypad or activate the Start remote input. The motor will start using the start
mode selected in Pr 2A.
7.2.1 Constant current
Constant current is the traditional form of soft starting, which raises the current from zero to a specified level and keeps the current
stable at that level until the motor has accelerated.
Constant current starting is ideal for applications where the start current must be kept below a particular level.
Figure 7-1 Constant current soft start
700% 3
600%
500%
400%
300%
1
200%
100%
10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Rotor speed (% full speed)
Digistart IS User Guide
Issue: 4
Electrical Keypad Quick Start
Installation and Commissioning
Status
Parameter Controlled
Voltage
Current
Torque
Acceleration
2
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Operation Programming Diagnostics Application
Performance Parameters Influenced
Start current, start torque, acceleration
Start torque, acceleration
Start current, acceleration
Start current, start torque
Constant Current
Adaptive Control
1: Initial current (Pr 2C)
2: Current limit (Pr 2B)
3: Full voltage current
Technical Maintenance Options
Examples Data
Use
37