Why is the first step always receding when the motor is on the power supply, and moving forward
The motor itself is permanent magnet, and the electromagnetism on the motor will allow him to return to the nearest basic step position. It's always possible.
The main reason: Step 1: the step motor is driven by the step drive, which is driven by a single chip or PLC by the HZ waveform. The waveform emitted by a PLC or a single chip is not "likely to be a program" (broken and lost). There is a problem with the step drive or step motor.
In general, without electricity, stepping motor is relaxed, not necessarily in any Angle. And the starting position of the battery is set by the hardware and software in the controller, and certainly not exactly the same Angle that it stopped. So when you get on the electricity, you're always going to move. But this "move" does not always have to be "backward". It happens that you're "always backing away". If software design is clever, this can be eliminated. Method is: before each blackout, the Angle of the software to record the current (phase) stored in the nonvolatile memory block (EEPROM), and just read the last saved when electricity phase, according to the given initial drive electrical signals. This way, you can't "move" when you are on electricity, as long as there is no external force on the motor during the power outage.
