Trinamic TMCM-342, Руководство пользователя

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TMCM-342 Manual V1.01 24/26
Copyright © 2008, TRINAMIC Motion Control GmbH & Co. KG
8 TMCM-342 Operational Description
8.1 Calculation: Velocity and Acceleration vs. Microstep- and
Fullstep-Frequency
The values of the parameters, sent to the TMC428 do not have typical motor values, like rotations per
second as velocity. But these values can be calculated from the TMC428-parameters, as shown in this
document. The parameters for the TMC428 are:
Signal Description Range
f
CLK
clock-frequency 0..16 MHz
velocity - 0..2047
a_max maximum acceleration 0..2047
pulse_div divider for the velocity. The higher the value is, the
less is the maximum velocity
default value = 0 0..13
ramp_div divider for the acceleration. The higher the value is,
the less is the maximum acceleration
default value = 0 0..13
Usrs microstep-resolution (microsteps per fullstep = 2
usrs
) 0..7 (a value of 7 is internally
mapped to 6 by the TMC428)
Table 8.1: TMC428 Velocity parameters
The microstep-frequency of the stepper motor is calculated with
32 2048 2
velocity ] Hz [ f
] Hz [ usf
div _ pulse
CLK
where “usf” means microstep-frequency
To calculate the
fullstep-frequency from the microstep-frequency, the microstep-frequency must be
multiplied with the number of microsteps per fullstep.
usrs
2
] Hz [ usf
] Hz [ fsf
where “fsf” means fullstep-frequency
The change in the pulse rate per time unit (pulse frequency change per second – the
acceleration a is
given by
29 div _ ramp div _ pulse
max
2
CLK
2
a f
a
This results in an acceleration in fullsteps of:
usrs
2
a
af
where “af” means acceleration in fullsteps