Is additional rotation monitoring required when stepper motors are used?
Support » FAQ » Stepper motors
If a stepper motor is correctly dimensioned, it provides an absolutely reliable drive element. If stepper motors are overloaded, however, the assignment to the setpoint position is permanently lost. This behavior is described as "step offset" and is deemed to be a serious disadvantage of the stepper motor because the out-of-position cannot be detected due to the open control chain.
Through an additional measuring system with an rotary encoder/encoder, however, any deviations are detected by comparison of the measured actual position and the requested setpoint position and corrected by a subsequent control process.
Nanotec offers extremely economic and high-resolution encoders for speed monitoring. The incremental 2-channel and 3-channel encoders offer here a low-priced solution with durable function and high measuring accuracy. The encoders are available in a small version with low masses and a high resolution, they are suitable for a wide temperature range and are resistant to swing accelerations. For later attachment all motors with a rear end shaft already have appropriate mounting holes on the rear panel cover for easy and fast construction.
Speed monitoring with automatic correction is already integrated in the Plug & Drive motors.
The stepper motor positioning controls of the SMCI series have an encoder input and can evaluate a 5 V TTL signal.
If a direct measuring system is installed on the machine, errors and non-linearities of the mechanics are also balanced within the context of the measuring accuracy.
