Control locations and operating modes 25
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 20.01…20.10. The operating mode can be selected separately for each
location (in parameter group 19 Operation mode), 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 Ext1/Ext2 selection). 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 Panel reference conflict. The panel reference can be
separately limited by parameters in group 49 Panel port communication.
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 40 Process PID set 1 and 41
Process PID set 2 only have one setting for the control panel. Whenever the control
panel is selected as the setpoint source, operation resumes using the previous
setpoint.
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