SIGMATEK ST 151, Manual

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ST 151 S-DIAS STEPPER MOTOR OUTPUT STAGE
Page 28 02.12.2019
The ST 151 has an adaptive fast decay current controller, by which the optimal decay mode
is automatically used. Using the time required to reach the preset current value and the
configured ChopperOnTimeMin (T
ONMIN
) value, the current controller decides which decay
mode is used and whether FastDecayTime (T
FD
) is reduced, increased or maintained. The
ChopperOnTimeMin, maximum FastDecayTime and maximum FastDecayTimeFallingStep
for negative current value jumps can be configured via parameters. With the Chopper-
OffTime (T
CHOPPEROFF
) parameter, the current controller base frequency is defined.
When the motor windings are switched over the H-bridge, parasitic capacitances generate
current spikes during charging/discharging. For this reason, the current measurement is
deactivated for a constant time (Blanking Time T
BLANK
).