External Control - ABB ACQ580 Firmware Manual

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External control

When the drive is in external control, control commands are given through
• the I/O terminals (digital and analog inputs), or optional I/O extension modules
• the fieldbus interface (via the embedded fieldbus interface or an optional fieldbus
adapter module).
Two external control locations, EXT1 and EXT2, are available. The user can select
the sources of the start and stop commands separately for each location by setting
parameters 20.01...20.09. The operating mode can be selected separately for each
location, which enables quick switching between different operating modes, for
example speed and process PID control. Selection between EXT1 and EXT2 is done
via any binary source such as a digital input or fieldbus control word (parameter
Ext1/Ext2 selection). The source of reference is selectable for each operating mode
separately.
Communication fail functionality
The communication fail functionality ensures continuous process without
interruptions. If there is a communication loss, the drive automatically changes the
control location from EXT1 to EXT2. This enables process to be controlled, for
example, with the drive PID controller. When the original control location recovers,
the drive automatically switches control back to the communication network (EXT1).
Settings
• Parameters 19.11 Ext1/Ext2 selection (page 141); 20.01...20.09
Program features 39
19.11
(page 142).