237-00156 SofTec Microsystems SRL, 237-00156 Datasheet - Page 86

• Manufacturer Part Number: 237-00156
• Description: BOARD ISOLATION FOR ST7
• Manufacturer: SofTec Microsystems SRL
• Type: Optoisolation Boardr

Specifications of 237-00156

• Contents: *
• For Use With/related Products: STMicro ST7FMC Motor Control Device
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Parameter Name
Demagnetization
Time
Force Duty Cycle
during
Demagnetization
Duty Cycle
Stop Condition
Brake Level
All Software
Available when the “All Software” option above is selected. This time
should be longer than the physical demagnetization time of the motor,
but short enough not to delay the BEMF detection. For each target
speed there should be a different software demagnetization time.
MDREG register, 8 bits from DN7 to DN0.
During demagnetization, current circulating in windings where the
polarization doesn’t change may increase to a level which may
damage the motor. To avoid this situation, a dedicated duty cycle can
be applied during demagnetization. This feature is available in
Sensorless, Voltage mode.
Available when the “Force Duty Cycle during Demagnetization”
option above is enabled.
Free Wheeling
DC Current
Braking
Available when the “DC Current Braking” option above is selected.
Two of the three bridge legs are grounded and a PWM signal with 50%
duty cycle (maximum) is applied on the third leg’s high side switch.
In Voltage mode, the duty cycle is loaded in the MCPUH and
MCPUL registers.
In Current mode, the current reference is loaded in the MCPVH
and MCPVL registers.
Parameter Values/Description
In some situations (e.g. when the
“Hardware/Software” option is not safe
enough) it may be necessary to set a
demagnetization time. This demagnetization
time must always be equal to or higher than the
physical demagnetization time of the motor
winding. In addition, since the rotor speed will
affect directly the step time, it is important, for
each speed (or duty cycle in Open Loop, Voltage
mode or current reference in Open Loop,
Current mode) to set a corresponding software
demagnetization time (or duty cycle, or current
reference). If the demagnetization time is too
long, it will limit the speed that can be reached
by the motor. What all of this means is that,
when using software demagnetization, you
should not significantly modify the target speed,
duty cycle, or current reference in the real-time
settings (when the motor is running), but you
should instead stop the motor, change the
software demagnetization time and start the
motor again.
MCRB register, bit HDM at 0, bit SDM at 1.
After stop, the motor will continue to spin freely.
To slow down the motor quickly, this feature
allows to apply active braking.
AK-ST7FMC User's Manual
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