ABB ACS850 series, Firmware Manual

Page: 27 / 260

Control locations and operating modes 27
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External control
When the drive is in external control, control commands are given through the
fieldbus interface (via an optional fieldbus adapter module), the I/O terminals (digital
and analogue inputs), optional I/O extension modules or the drive-to-drive link.
External references are given through the fieldbus interface, analogue inputs, drive to
drive link and encoder inputs.
Two external control locations, EXT1 and EXT2, are available. The user can select
control signals (e.g. start and stop) and control modes for both external control
locations. Depending on the user selection, either EXT1 or EXT2 is active at a time.
Selection between EXT1/EXT2 is done via digital inputs or fieldbus control word.
Operating modes of the drive
The drive can operate in several control modes.
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Speed control mode
Motor rotates at a speed proportional to the speed reference given to the drive. This
mode can be used either with estimated speed used as feedback, or with an encoder
or resolver for better speed accuracy.
Speed control mode is available in both local and external control.
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Torque control mode
Motor torque is proportional to the torque reference given to the drive. This mode can
be used either with estimated speed used as feedback, or with an encoder or resolver
for more accurate and dynamic motor control.
Torque control mode is available in both local and external control.
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Special control modes
In addition to the above-mentioned control modes, the following special control
modes are available:
• Emergency Stop modes OFF1 and OFF3: Drive stops along the defined
deceleration ramp and drive modulation stops.
• Jogging mode: Drive starts and accelerates to the defined speed when the
jogging signal is activated.
For more information, see parameter group 10 Start/stop on page 79 .