ABB ACS880 Firmware Manual page 93

Any subsequent initialization of the counter must first be enabled by
counter init ready. To define a time window for initializations,
counter initialization
active fault in the drive will also prevent counter initialization.
Encoder error handling
When an encoder is used for load feedback, the action taken in case of an encoder
error is specified by
calculation will continue smoothly using estimated motor position. If the encoder
recovers from the error, the calculation will smoothly switch back to encoder
feedback. The load position signals (90.04,
updated all the time, but bit 6 of
potentially inaccurate position data. In addition, bit 4 of
next stop as a recommendation to reinitialize the position counter.
Parameter 90.60 Pos counter error and boot action
calculation resumes from the previous value over an encoder error or control unit
reboot. By default, bit 4 of
indicating that reinitialization is needed. With
value, the position values are retained over an error or reboot; bit 6 of
counter status is set however to indicate that an error occurred.
Note: With a multiturn absolute encoder, bit 6 of
the drive if the encoder has recovered from the error; bit 4 is not cleared. The status
of the position counter is retained over a control unit reboot, after which position
calculation resumes from the absolute position given by the encoder, taking into
account the initial position specified by 90.58.
WARNING! If the drive is in stopped state when an encoder error occurs, or if
the drive is not powered, parameters 90.04, 90.05,
updated because no movement of the load can be detected. When using previous
position values (90.60 Pos counter error and boot action
previous value), be aware that the position data is unreliable if the load is able to
move.
Reading/writing position counter values through fieldbus
You can access the parameters of the position counter function, such as
position scaled and
the following formats:
• 16-bit integer (if 16 bits are sufficient for the application)
• 32-bit integer (can be accessed as two consequent 16-bit words).
For example, to read parameter
selection parameter of the desired dataset (in group 52) to Other – 90.07, and select
the format. If you select a 32-bit format, the subsequent data word is also
automatically reserved.
can be used to inhibit the signal from the proximity switch. An
90.55 Load feedback
90.35 Pos counter status
90.35 Pos counter status
90.65 Pos counter init value
90.05 Load position scaled
Standard program features 93
fault. If the parameter is set to Warning, the
90.05 and 90.07) will continue to be
will be set to indicate
90.35
defines whether position
is cleared after an error,
90.60 set to Continue from previous
90.35 is cleared at the next stop of
90.07
is set to Continue from
from an upper-level control system in
90.69 Reset pos
90.68 Disable pos
will be cleared upon the
90.35 Pos
and 90.35 are not
90.05 Load
through fieldbus, set the