Motion controller suits steppers and piezo-electric motors

Paul Boughton
Trinamic is introducing the TMC457 motion controller that is suitable for traditional stepper motors as well as for piezo-electric motors, such as the Piezolegs family from the Swedish company Piezo Motors. The device can generate linear and S-shaped acceleration and braking ramps, making it suitable for applications requiring fast, dynamic motion without sudden acceleration changes.

The TMC457 accepts digital quadrature signals from incremental encoders over its integrated encoder interface. The measured position is processed directly by the on-board easyPID controller and is software-readable from a register. PID parameters and all other motion parameters are programmable and can be changed 'on the fly,' even in the midst of acceleration or braking. This characteristic simplifies the development of control software dramatically.

Unlike conventional stepper motors, piezo motors do not have a fixed step size. Consequently the TMC457 supports different integration parameters for the step sizes of motor and encoder. Using this capability together with encoder feedback, direct positioning in the nanometre range is possible.

Users need only to provide the software for movement control parameters and the chosen communication bus protocol. The fast PID controller works at a 16MHz clock frequency with a cycle rate of 100kHz. A high cycle rate is necessary with fast movements or highly resolvable movements and any combination of the two.

The TMC457 can be connected directly to any of Trinamic's stepper motor drivers, such as the TMC236, TMC239, TMC246, or TMC249. The device includes Trinamic's Chopsync function that allows high-speed operation without resonance problems. In addition there is an S/D output for drivers.

Because of the high resolution of the microstep size, the TMC457 is particularly suitable for applications requiring extreme precision, such as semiconductor processing equipment, biotech laboratory automation or optics.

For more information, visit www.trinamic.com