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4 Functional Description
4.4 Enhanced operating modes
Absolute positioning within one revolution:
Thanks to the linear Hall sensors, the absolute position can be recorded within one revolution on BL
motors. This means that even if the power supply is disconnected, the position determination sup-
plies the correct position value after restarting (if the rotor has only been turned within one revolu-
tion).
The following commands enable the drive to be accurately positioned in the voltage range 0 V to
10 V within one revolution and to return to the correct position even after the supply has been
switched off, without homing (not MCDC):
APCMOD
… change to analog positioning
LL3000
… Fix maximum position at 1 revolution (for COMPATIBLE1: LL1000)
4.4.4 External encoder as actual value (not MCDC)
For high-precision applications, the actual values of BL motors can be derived from an external
encoder.
The resolution of the position values is dependent on the resolution of the encoder in this case.
Depending on the application, the velocity can be derived from the encoder or from the Hall sen-
sors.
The external encoder can be mounted directly on the motor shaft, but an encoder that is mount-
ed to the application output (e.g. glass scale) is particularly advantageous. This allows the high
precision to be set directly at the output.
Commutation still occurs via the analog Hall sensors.
Command
Function
Description
ENCMOD
Encoder Mode
Change to encoder mode (not for MCDC) An external
encoder serves as position transducer (the current
position value is set to 0)
HALLSPEED
Hall sensor as speed sensor
Speed via Hall sensors in encoder mode (not for
MCDC)
ENCSPEED
Encoder as speed sensor
Speed via encoder in encoder mode (not for MCDC)
The two channels of the external encoder are connected to connections AnIn and AGND, which may
need to be connected to the 5 V encoder supply via a 2.7 k
pull-up resistor.
The maximum limit position (value preset with the LL command) covers the value range from 0 to
1 800 000 000 for the positive and 0 to –1 800 000 000 for the negative limit position.
Input:
Maximum input frequency: 400 kHz
Level: low 0…0.5 V / high 3.5 V… U
B
Set encoder resolution:
Command Function
Description
ENCRES
Load Encoder Resolution
Load resolution of external encoder.
(4 times pulse/rev.).
Value: 8 to 65 535
Example:
External encoder with 512 pulses:
ENCRES2048
Because of the quadrature signal processing, four times the number of pulses must always be speci-
fied for ENCRES.
