Datasheet

TMC4361A Datasheet | Document Revision 1.22 • 2017-JAN-12
168/230
© 2015 TRINAMIC Motion Control GmbH & Co. KG, Hamburg, Germany — Terms of delivery and rights
to technical change reserved. Download newest version at: www.trinamic.com .
Read entire documentation; especially the “Supplemental Directives” on page 224.
 MAIN MANUAL 
In case an encoder is connected, REAL motor velocity can be read out. The actual
encoder velocity flickers. This is system-immanent. TMC4361A provides filter options
that back-EMF compensation is based on. The following velocity parameters can be
read out.
Actual encoder velocity in pulses (microsteps) per second [pps].
Actual filtered encoder velocity in pulses (microsteps) per second [pps].
In order to set filter parameters correctly, consider the following details:
ENC_VMEAN_WAIT represents the delay period in number of clock cycles between
two consecutive V_ENC values that are used for the encoder filter velocity calculation.
The lower this value, the faster the adaptation process of V_ENC_MEAN is.
Accordingly: The higher the gradient of V_ENC_MEAN is.
In case incremental ABN encoders are connected, ENC_VMEAN_WAIT must be set
above 32.
In case absolute encoders are connected, ENC_VMEAN_WAIT is automatically set to
SER_PTIME .
This filter exponent is used for filter calculations. The lower this value, the faster the
adaptation process of V_ENC_MEAN is. Accordingly: The higher the gradient of
V_ENC_MEAN is. Every ENC_VMEAN_WAIT clock cycles, the following calculation
applies:



 













The refresh frequency of high encoder velocity values V_ENC is determined by this
encoder velocity update period.
In case incremental ABN encoders are connected, the minimum value of
ENC_VMEAN_INT is automatically set to 256.
In case absolute encoders are connected, ENC_VMEAN_INT is automatically adapted
to encoder value request rate.
Because internal calculation of low V_ENC values is triggered by AB signal changes
and not by the refresh frequency defined by ENC_VMEAN_INT , any occurring idle
state of the encoder is not recognized.
In order to determine that V_ENC = 0, it is possible to limit the number of clock cycles
while no AB signal changes occur; which then signifies encoder idle state.
In order to evoke encoder idle state, do as follows:
Action:
 Set proper ENC_VEL_ZERO register 0x62.
Result:
In case no AB signal changes occur during ENC_VEL_ZERO clock cycles, ENC_VEL0
event is triggered, which indicates encoder idle state.
Encoder Velocity
Readout
Parameters
V_ENC 0x65
V_ENC_MEAN
0x66
Encoder Velocity
Filter
Configuration
ENC_VMEAN_WAIT
0x63 (7:0)
ENC_VMEAN_FILTER
0x63 (11:8)
ENC_VMEAN_INT
0x63 (31:16)
Encoder Velocity
equals 0 Event