TMC423 Data Sheet – (V1.13 / June 20th, 2007)
11/22
4 Dynamic Resolution Adaptation
The dynamic resolution adaptation is needed to link stepper motors and encoders with different
resolutions. The characteristics of the connected hardware must provided to the TMC423 by sending
the corresponding SPI telegram. (See 5.3.1 Overview on page 13 in this issue). The TMC423 multiplies
the encoder counter by a user selectable value in the range 1..1024, and then divides it by 16. When
using incremental encoders with N channel it is also possible to select between different behaviors
when the N channel is triggered.
Encoder:
Resolution: e.g.: 1000 steps / rotation
Stepper
TMC423
SPI Interface
motor
TMC423:
Prescaler = 3.2 -> 1000* 4 * 3.2 = 12800
Stepper Motor:
Resolution: e.g.: 12800 steps / rotation
Figure 6: TMC423 Application
Table 4 shows a number of prescaler factors for possible combinations of micro step resolution and
encoder resolution. Note: The given number of pulses have to be multiplied by four since 4-times
encoder signal evaluation is used. (See Figure 10: Encoder Output and Evaluation on page 14).
Microstep
s
Encoder Resolution [Pulses / Rotation]
1024
3.125
1.5625
----
----
----
1000
3.2
1.6
----
----
----
512
6.25
3.125
1.5625
----
500
6.4
3.2
1.6
----
----
----
256
12.5
6.25
3.125
1.5625
----
250
12.8
6.4
3.2
1.6
----
200
16
8
4
2
125
25.6
12.8
6.4
3.2
1.6
50
64
32
16
8
4
2
25
----
64
32
16
8
12800
6400
3200
1600
800
----
----
1
400
----
----
----
----
----
----
4
Table 4: Prescaler factors for different motors and encoders
Copyright © 2004 TRINAMIC Motion Control GmbH & Co. KG
TRINAMIC [ TRINAMIC MOTION CONTROL GMBH & CO. KG. ]
