ABB ACS880 Series, Firmware Manual

Page: 96 / 764

Continue from previous value , the position values are retained over an error or
reboot; bit 6 of 90.35 is set however to indicate that an error occurred.
Note: With a multiturn absolute encoder, bit 6 of 90.35 is cleared at the next stop
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
90.4 , 90.5 , 90.7 and 90.35 are not updated
because no movement of the load can be detected. When using previous
position values (
90.60 is set to Continue from previous value ), be aware that
the position data is unreliable if the load is able to move.
Reading/writing position counter values through fieldbus
The parameters of the position counter function, such as 90.7 and 90.58 , can be
accessed from an upper-level control system in 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 90.7 through fieldbus, set the selection parameter
of the desired dataset (in group 52 ) to Other – 90.7 , and select the format. If you
select a 32-bit format, the subsequent data word is also automatically reserved.
Configuration of HTL encoder motor feedback
1. Specify the type of the encoder interface module (parameter 91.11 = FEN-31 )
and the slot the module is installed into ( 91.12 ).
2. Specify the type of the encoder ( 92.1 = HTL ). The parameter listing will be
re-read from the drive after the value is changed.
3. Specify the interface module that the encoder is connected to ( 92.2 = Module
1 ).
4. Set the number of pulses according to encoder nameplate ( 92.10 ).
5. If the encoder rotates at a different speed to the motor (ie. is not mounted
directly on the motor shaft), enter the gear ratio in 90.43 and 90.44 .
6. Set parameter 91.10 to Refresh to apply the new parameter settings. The
parameter will automatically revert to Done .
7. Check that 91.2 is showing the correct interface module type ( FEN-31 ). Also
check the status of the module; both LEDs should be glowing green.
8. Start the motor with a reference of eg. 400 rpm.
96 Program features