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SDC Step Direction Control-head


control: closed-loop
sensor type: micro, nano
control panels: n x 1

Step-Direction Control for SmarAct Positioners

With the Step-Direction Control SDC and SDC2 we offer a low level control system to use SmarAct positioners like stepper motors. The standard inputs of the SDC controller are step and direction signals. So you can profit from the performance of our positioners with only minor changes to your own established control structure. For every step a closed-loop controlled position increment is performed in the specified direction. In order to get a position signal, the SDC2 supports a quadrature signal feedback.

Operation Mode


n x 1

feedback loop

open-loop, closed-loop

sensor support

-L, -S

Output Signals

voltage range

0 .. 100 V

maximum output current

360 mA / channel

position feedback

square shape signal, quadrature feedback (SDC2)


positioner interface

1 x DSUB 15, female

control interface

5 V TTL or open collector
RS232 for configuration

power supply

12-24 V, 60 W (with 19″ rack up to 600W)

Integration of Controller

interface board

euro-sized board with DSUB9 for CLK / DIR (-EUR)
MAXV controller board with SCSI connector (-MAX)


single channel board, adapter board for two SDC boards


table-top (-TAB), single control board (-OEM), 19″ rack module (-MOD)


software / drivers

SDC configuration program for Windows®

data cable

1.5 m RS232 cable

data cable

1.5 m USB / RS232 cable

AC adapter

100 .. 240 V, 50 .. 60 Hz together with table-top unit

SDC Architecture – Step-Direction Control for Piezo Motors

SDC Architecture
The SDC 2 reads-in step-direction signals (1) from a stepper motor controller and then generates signals that drive the positioners.

The position change in the positioner then leads to a sinus / cosinus signal of the integrated optical sensor (2). This signal is then digitized and transmitted with a serial RS485 data stream to the SDC 2 controller.

Based on this position feedback the SDC 2 controller performs a closed-loop position control and outputs quadrature signals (3).

The SDC 1 controller works in a similar way but without the quadrature feedback.