User Manual

TMCM-1210 TMCL
™
Firmware Manual • Firmware Version V1.11 | Document Revision V1.00 • 2017-JUN-19
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6 Module Specific Hints
This section contains some hints that are specific to the TMCM-1210 module.
6.1 Accuracy of Velocity Values
Due to the limited board space, the TMCM-1210 module does not use a crystal for clock generation.
Instead, the ramp generator (TMC5130) runs on its internal clock. Although temperature stable, this clock
is slightly different on each chip and hence different on each module. To overcome this, the clock is
calibrated when the module is tested after production. A correction factor for velocity and acceleration
is then saved in the flash memory of the CPU and automatically used when the module is in pps mode
(axis parameter #255 set to 1 (default value)). So, velocity values given in pps are highly accurate also on
different TMCM-1210 modules.
When pps mode is turned off by setting axis parameter #255 to 0 (normally not recommended), the speed
is given directly using the internal units of the TMC5130. In this case, no correction factor is used, and the
same speed value can lead to slightly different speeds on different TMCM-1210 modules.
6.2 Accuracy of Acceleration Values
A correction factor similar to the velocity correction factor (as described in the previous section) is used for
all acceleration values when pps mode is active (axis parameter #255 set to 1 (default value)). This also
leads to a good accuracy of acceleration values given in pps
2
. But due to range limitations in the TMC5130
motion controller (0. . . 65535), the accuracy of the acceleration values is not as high as the accuracy of the
velocity values. This leads to the fact that acceleration values read back using GAP are sometimes sligthly
different from those set with SAP. This slight difference is normally not a problem. Furthermore, when
setting the same acceleration value on different TMCM-1210 modules the value read back can be slighly
different between the modules. This is caused by the different correction factors and is also not a problem.
When pps mode is turned off by setting axis parameter #255 to 0 (normally not recommended), the
acceelration is given directly using the internal units of the TMC5130. In this case, no correction factor is
used, and the same acceleration value can lead to slightly different accelerations on different TMCM-1210
modules.
6.3 Limitations of the Encoder
The built-in magnetic encoder on the PD-1210 PANdrives has some limitations concerning the maximum
rotation speed. When this limit is exceeded, the position counter (axis parameter #209) will not count
correctly any more. It will count correctly again when the speed falls below this limit. The absolute encoder
value (axis parameter #215) is always correct.
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