External Control; Using The Control Panel As An External Control Source - ABB ACS880 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 embedded fieldbus interface or an optional fieldbus adapter module
• the external (DDCS) controller interface
• the master/follower link, and/or
• the control panel.
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 parameters
20.1...20.10. The operating mode can be selected separately for each location (in
parameter group 19) which enables quick switching between different operating modes,
for example speed and torque control. Selection between EXT1 and EXT2 is done via
any binary source such as a digital input or fieldbus control word (see parameter 19.11).
The source of reference is selectable for each operating mode separately.
The control location selection is checked on a 2 ms time level.

Using the control panel as an external control source

The control panel can also be used as a source of start/stop commands and/or reference
in external control. Selections for the control panel are available in the start/stop
command source and reference source selection parameters.
Reference source selection parameters (except PID setpoint selectors) have two
selections for the control panel. The difference between the two selections is in the initial
reference value after the reference source switches to the control panel.
The panel reference is saved whenever another reference source is selected. If the
reference source selection parameter is set to Control panel (ref saved), the saved value
is used as the initial reference when control switches back to the panel. Note that only
one type of reference can be saved at a time: for example, attempting to use the same
saved reference with different operating modes (speed, torque, etc.) causes the drive
to trip on 7083. The panel reference can be separately limited by parameters in group
49.
With the reference source selection parameter set to Control panel (ref copied), the
initial panel reference value depends on whether the operating mode changes with the
reference source. If the source switches to the panel and the operating mode does not
change, the last reference from the previous source is adopted. If the operating mode
changes, the drive actual value corresponding to the new mode is adopted as the initial
value.
The process PID setpoint selectors in parameter groups
for the control panel. Whenever the control panel is selected as the setpoint source,
operation resumes using the previous setpoint.
Control locations and operating modes 25
40 and 41 only have one setting