How to Reverse motor direction in mcedesigner for a demo?

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User19241
Level 2
Level 2
10 replies posted 5 replies posted 5 questions asked
I'm using EVAL-M1-101T driving EVAL-M1-CM610N3 and BLDC motor.
I managed to go thru the wizard and start and even change speed of motor in MCEdesigner via Target Speed. That works great.
Now How to set a REVERSE direction speed?
I would think I'd be able to REVERSE the motor via a negative value entered for target speed as the value RANGE for TARGET SPEED does indeed include negative numbers.
But so far a negative number entered on the fly stops the motor. If I stop and start the motor with a negative TARGET SPEED value, the motor defaults to the same direction and some default speed.

Note: My MIN SPEED is set to 500. I notice that RANGE is only positive numbers from 0 to 16383.
Is it NOT allowing me to reverse direction because the MIN SPEED is only a positive range?
What am I missing?
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1 Reply
Casey
Employee
Employee
50 replies posted 25 replies posted 10 replies posted
dwissel wrote:
I'm using EVAL-M1-101T driving EVAL-M1-CM610N3 and BLDC motor.
I managed to go thru the wizard and start and even change speed of motor in MCEdesigner via Target Speed. That works great.
Now How to set a REVERSE direction speed?
I would think I'd be able to REVERSE the motor via a negative value entered for target speed as the value RANGE for TARGET SPEED does indeed include negative numbers.
But so far a negative number entered on the fly stops the motor. If I stop and start the motor with a negative TARGET SPEED value, the motor defaults to the same direction and some default speed.

Note: My MIN SPEED is set to 500. I notice that RANGE is only positive numbers from 0 to 16383.
Is it NOT allowing me to reverse direction because the MIN SPEED is only a positive range?
What am I missing?


Changing the direction requires the speed to go down to zero before starting up in reverse direction. When motor speed is too low or motor is stopping, back EMF is too low for flux estimator and PLL to work reliably. It would lose track of speed and fail to restart the motor. Theres two ways you could approach this.
You could change the target speed in the start sequence to change the direction during start-up: On the left side of MCEDesigner, open the start motor function and change the target speed there by putting your negative rpm.
Another option is to create a new function in MCEDesigner by right clicking "User application function definitions" and executing this function even if the motor is already running:
Command = 0
Delay = 1000 ms
TargetSpeed = -???
Command = 1
This sequence will restart the motor in reverse direction following the same start-up sequence that worked before in forward direction. The delay time will need to be adjusted for motor to come to a full stop.
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