User`s manual

DS2100 User's Manual SECTION 5: DS2100 FUNCTIONAL OVERVIEW
PAGE 5-24
5.6.1.7 Direction of rotation
The direction of rotation can be reversed with the parameter encoder_direction_of_rotation
(index 0x2e20, subindex
4). Normally positive direction is clockwise rotation when looking onto the encoder shaft. In this case is channel
B leading the channel A signals. If the direction has to be changed because of different encoder signals or
mounting of the encoder on the motor or machine, encoder_direction_of_rotation
can be set to 1. This reverses the
direction so that positive direction is counter clockwise rotation when looking onto the encoder shaft. The change
of direction affects the encoder position, the encoder velocity and the encoder commutation angle.
0 - normal direction: positive position count when rotating clockwise looking
onto the encoder shaft
1 - reversed direction: positive position count when rotating counter clockwise
looking onto the encoder shaft
5.6.1.8 Number of data stream bits for SSI encoders
For SSI encoders the number of bits in the data stream has to be set using the parameter encoder_ssi_number_bits
(index 0x2e20, subindex 6). It contains the number of bits in the raw data stream (not the number of encoder
position bits !). See encoder manufacturers manual for further information.
5.6.1.9 Data encoding for SSI encoders
The encoding can be changed between binary and Gray code transmission with the parameter encoder_ssi_coding
(index 0x2e20, subindex 7). The following values are possible:
0 - Gray code
1 - Binary code
See encoder manufacturers manual for further information.
5.6.1.10 Position bit mask for SSI encoders
Depending on the encoder, not all bits in the SSI data stream contain position information. To accommodate this,
the parameter encoder_ssi_data_bit_mask
(index 0x2e20, subindex 8) has to be set to mask off all the unused bits in
the raw data stream. A one in encoder_ssi_data_bit_mask
means that the bit contains position information. The
least significant bit in encoder_ssi_data_bit_mask
corresponds to the last bit clocked out of the encoder. Bits above
the number set in encoder_ssi_number_bits
are 'don't care'; they are ignored.
5.6.1.11 Encoder commutation position
The encoder can also be used for commutation of the motor (motor phase current change depending on rotor angle
position). The parameter encoder_commutation_position
(index 0x2e20, subindex 11) contains a 16-bit value that
represents a full mechanical revolution independent of the encoder resolution setting encoder_resolution
. The
encoder direction of rotation parameter encoder_direction_of_rotation
also changes the direction for the encoder
commutation position.