MC3PHAC Motorola, MC3PHAC Datasheet - Page 35

• Manufacturer Part Number: MC3PHAC
• Description: 3-Phase AC Motor Controller
• Manufacturer: Motorola

Command State Machine
MOTOROLA
When using the PC master software mode of operation, the command state
machine governs behavior of the device depending upon its current state,
system parameters, any new commands received via the communications link,
and the prevailing conditions of the system. The command state diagram is in
Figure
bring the device from the reset condition to running the motor in a steady state
and depicts the permissible state transitions. The device will remain within a
given state unless the conditions shown for a transition are met.
Some commands only cause a temporary state change to occur. While they are
being executed, the state machine will automatically return to the state which
existed prior to the command being received. For example, the motor speed
may be changed from within any state by using the WRITEVAR16 command to
write to the "Speed In" variable. This will cause the "Set Speed" state to be
momentarily entered, the "Speed In" variable will be updated and then the
original state will be re-entered. This allows the motor speed, acceleration or
base frequency to be modified whether the motor is already accelerating,
decelerating, or in a steady state.
Each state is described here in more detail.
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Reset — This state is entered when a device power-on reset (POR), pin
reset, loss of crystal, internally detected error, or reset command occurs
from within any state. In this state, the device is initialized and the PWM
outputs are configured to high impedance. This state is then
automatically exited.
PWMHighZ — This state is entered from the reset state. This state is
also re-entered after one and only one of the PWM dead-time or polarity
parameters have been initialized. In this state the PWM outputs are
configured to a high-impedance state as the device waits for both the
PWM dead time and polarity to be initialized.
SetDeadTime (write once) — This state is entered from the PWMHighZ
state the first time that a write to the PWM dead-time variable occurs. In
this state, the PWM dead time is initialized and the state is then
automatically exited. This state cannot be re-entered, and hence the
dead time cannot be modified, unless the reset state is first re-entered.
SetPolarity (write once) — This state is entered from the PWMHighZ
state the first time that the PWM polarity command is received. In this
state, the PWM polarity is initialized and the state is then automatically
exited. This state cannot be re-entered, and hence the polarity cannot
be modified, unless the reset state is first re-entered.
18. It illustrates the sequence of commands which are necessary to
3-Phase AC Motor Controller
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MC3PHAC/D
Operation
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