84 Program features
Tracking
In tracking mode, the PID block output is set directly to the value of parameter
40.50
Set 1 tracking ref selection
(or
41.50
Set 2 tracking ref selection
).The internal I term
of the PID controller is set so that no transient is allowed to pass on to the output, so
when the tracking mode is left, normal process control operation can be resumed
without a significant bump.
Settings
Parameter
96.04
Macro select
(page
332
).
Parameter groups
40 Process PID set 1
(page
259
) and
41 Process PID set 2
(page
273
).
Mechanical brake control
A mechanical brake can be used for holding the motor and driven machinery at zero
speed when the drive is stopped, or not powered. The brake control logic observes
the settings of parameter group
44 Mechanical brake control
as well as several
external signals, and moves between the states presented in the diagram on
page
85
. The tables below the state diagram detail the states and transitions. The
timing diagram on page
87
shows an example of a close-open-close sequence.
For application example, see section
Crane mechanical brake control
on page
533
.
Inputs of the brake control logic
The start command of the drive (bit 5 of
06.16
Drive status word 1
) is the main control
source of the brake control logic. An optional external open/close signal can be
selected by
44.12
Brake close request
. The two signals interact as follows:
• Start command = 1
AND
signal selected by
44.12
Brake close request
= 0
→
Request brake to
open
• Start command = 0
OR
signal selected by
44.12
Brake close request
= 1
→
Request brake to
close
Another external signal – for example, from a higher-level control system – can be
connected via parameter
44.11
Keep brake closed
to prevent the brake from opening.
Other signals that affect the state of the control logic are
• brake status acknowledgment (optional, defined by parameter
44.07
Brake
acknowledge selection
),
• bit 2 of
06.11
Main status word
(indicates whether the drive is ready to follow the
given reference or not),
• bit 6 of
06.16
Drive status word 1
(indicates whether the drive is modulating or
not).
ACS380 FW.book Page 84 Friday, May 4, 2018 4:18 PM
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