Phase Memory Function Of Stepper Motor Controller

- Jul 31, 2018-

Phase memory function of stepper motor Controller

The stepper motor driver restarts the stepper motor after the power is turned off, and the stepping motor may be shaken. To explain the cause of this phenomenon and solve it, it is necessary to understand the stepper motor driver phase memory function .

This article details the phase memory function. Phase memory, we can imagine how many degrees a stepper motor will take after one step, and it must stop at that angle when stopping.

When the stepper driver is powered off at a certain phase, if the phase is different from the phase at the next power-on, the stepper motor will “jitter”. In order to eliminate this jitter, it is necessary remember the phase when turn off the power. For example, the timing of the operation stepper motor is 8, assuming that it stops at step 4 and  power off. After power-on again, if the first step is started directly at the 4th position, it will appear a step jump. If the system can remember that it is still in step 4, then can correctly issue the command to go to step 5 or step 3.

At present, there is a large number of stepper motor drivers that do not have a power-down phase memory function, especially a stepper driver that uses a common dedicated IC. For example, it is not a chip-type driver now, and belongs to the DSP vertical drive does not have phase memory, that is, it stops at the phase when his pulse is finished. Because the motor is slightly inertia when it stops, it staggers the point of memory.

The reset signal of the reset pin after power-on of the IC resets the motor phase to the initial value, and the jitter of the power-on should be unavoidable. Even if it is an absolute value servo motor, it has to be judged and corrected.

It can also be seen as jitter. Or strictly speaking, there is no motor that does not shake on power. The key is how much impact does this jitter have on your application? It is best to record the absolute stop coordinates, after power-on

the system resets and check original point and then runs to the absolute coordinate recovery operation before the power is turned off.

If the jitter has a large impact on the overall operation, it is recommended to consider the servo motor. The servo motor has a Z phase, which can stay in absolute value or find 0 point to avoid power-on jitter.

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