User Manual

PD42-x-1140 Hardware Manual (V1.03 / 2018-JAN-25) 9

4.3 Integrated sensOstep™ encoder

The PD42-x-1140 PANdrives offer integrated sensOstep™ encoders based on hall sensor technology. As the

name “sensOstep™” already indicates intended use of this type of compact and highly integrated encoder is

step loss detection of motor movements. As soon as the motor has been moved to a new location the position

may be verified using this encoder feedback. In case the stepper motor has lost one or multiple steps during

movement e.g. due to overload / any obstacle encountered during movement the motor axes will jump for at

least one electrical period / 4 full steps. This can be detected using the integrated encoder. In addition, step

losses may be already detected during motor movements using the “deviation” setting available as part of the

TMCL firmware (see PD42-x-1140 / TMCM-1140 firmware manual for more details).

While the encoder offers 10bit (1024 steps) resolution per motor revolution the absolute position information is

less accurate and depends on the displacement of the hall sensor based encoder IC relative to the magnet and

motor axis among other factors. Every PANdrive™ has been tested for maximum deviation of +/- 5 encoder

steps (static performance) relative to commanded microstep target position during final tests after assembly at

our factory. This will ensure more than adequate performance of the integrated sensOstep™ encoder for step

loss detection during motor movements.

Do not disassemble PANdrive™ when using integrated encoder

In order to make proper use of the integrated sensOstep™ encoder (the sensor IC is placed

on the bottom center of the pcb) the TMCM-1140 electronics should not be removed/moved

relative to the motor! Otherwise encoder performance might suffer / not work.

Note: In case the integrated encoder feature is not used, the TMCM-1140 electronics may be

moved or even removed from the motor and placed somewhere else according to

application requirements.

Keep the electronics free of (metal) particles!

The integrated sensOstep™ encoder uses a magnet at the end of the motor axis in order to

monitor position of the motor axis. The magnet naturally attracts especially tiny metal

particles. These particles might be held on the top side of the PCB and even worse – start

moving in accordance with the rotating magnetic field as soon as the motor starts moving.

This might lead to shorts of electronic contacts / wires on the board and totally erratic

behavior of the module! Use compressed air for cleaning the module if necessary (especially

in prototype setups).

In order to prevent shorts and better protect the electronics the TMCM-1140 printed circuit

board is coated after assembly of components since hardware version V1.3.