By adding an inexpensive encoder to a step motor system, the drive can monitor the motor’s actual position directly, closing the feedback loop and avoiding many of the limitations traditionally associated with stepper systems. To make encoder feedback even easier, we’ve released a new video demonstrating three ways you can use it and how to set it up.
The first use of encoder feedback is for position and velocity verification. A PC or PLC can monitor position and velocity by connecting to one of our ST or STAC drives by RS-232, RS-485, CANopen, Ethernet or EtherNet/IP.
The second use of encoder feedback is the immediate detection and reporting of stalls in the event that the motor is overloaded. The video shows how the driver can be configured to signal other equipment by the state change of a digital output or by providing this information over the communication interface.
The third and ultimate use of encoder feedback uses the encoder for real time monitoring of the torque producing lead/lag angle, the angular difference between the magnetic fields of the stator and rotor. Applied Motion drives can use this information to precisely control the motor’s torque and prevent unexpected motor stalls. Stall prevention is enabled by checking the “Stall Prevention” box in our free ST Configurator set up software (see image).
An added benefit of Applied Motion’s encoder feedback solution is the ability to use the encoder index to achieve precise homing, accurate to 0.09 degrees.
Encoders can be purchased with Applied Motion motors ranging from NEMA size 11 to 34. The encoder comes pre-assembled to the rear shaft of the step motor and connects via cable to the encoder feedback port available on many of our drives, including our DC powered ST5 and ST10 and the AC powered STAC5 and STAC6. Internal encoders are also available on the STM17, STM23 and STM24 integrated drive+motor and support the same features as the ST and STAC products.