PD-013-42 / TMCM-110-42 Manual (V1.24/2011-NOV-25)
17
Copyright © 2011, TRINAMIC Motion Control GmbH & Co. KG
which is significantly lower than the motor maximum coil current. If it is too high, the motor has significant
magnetization losses and coil power dissipation, and would get much too hot, even with zero average
current. The only possibility to limit this effect is to operate with a comparatively low supply voltage.
Check list:
Follow the motor inductivity L [mH] and motor rated full step coil current I
COIL
[A] of the motor data sheet.
Now, choose a supply voltage for the module to fulfill the following comparison:
5
.
0
25
COIL
S
I
L
s
V
L
k
I
V
COIL
S
20
If your parameters do not fulfill the equation, i.e. you calculate a supply voltage which is below the
modules’ operation specs or which does not fit your system requirements, try the following.
Calculate x:
mH
L
I
V
x
COIL
S
025
.
0
-
If x is below 0.5, everything is OK.
-
If x is in the range 0.5 to 1.0 try operating your motor and check if motor or driver get too hot.
-
If x is above 1.0 choose one of the other chopper modes.
See chapter 7.4 for graphical demonstration, also.
7.3.4
Chopper mode 3 (Phase and SPI)
This mode combines the modes 2 (Phase) and 0 (SPI) in order to provide highest accuracy at lower
velocities and also the possibility for faster movements. Through the switching between modes some
microsteps may be lost. Microstep resolution must not be higher than 64. It is set according to Phase mode,
so possible values for Z (microstep resolution) are 2, 3 or 4.
µsteps
Phase to SPI
SPI to Phase
V-value
Rounds/s
V-value
Rounds/s
64
192000
2.24
25000
0.29
32
96000
2.24
12500
0.29
16
48000
2.24
6250
0.29
Table 7.11: Chopper mode 3 switching velocities
Conversion of values above to motors with different fullstep resolutions:
revolution
per
fullsteps
motors
s
rounds
v
s
rounds
v
table
motor
200
)
/
(
)
/
(
7.3.5
Chopper mode 4 (PWM and SPI)
This mode combines the modes 1 (PWM) and 0 (SPI) in order to provide higher accuracy (up to 64
microsteps) at lower velocities and also the possibility for faster movements. For higher velocities in SPI
mode the microstep resolution is always 16, but set resolution is simulated. Through the switching between
modes some microsteps may be lost. Microstep resolution must not be higher than 64. It is set according to
Phase mode, so possible values for Z (microstep resolution) are 2, 3 or 4. This mode should only be used in
very special occasions and mode 3 should be preferred if a combination of high accuracy at slow
movements and high speed is needed.
