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A project log for STEbus Servo Motor Controller

Based on the Galil GL2000/GL2010/GL1000 controller chip set. Professional design by me.

KeithKeith 11/04/2021 at 12:340 Comments


The SEMC and SEMC-10 use an intelligent LSI chip set which provides all the functions required to drive a servo motor without interaction from the host computer. It has inputs for an encoder and resolver, and produces a control voltage and pulse signals to drive a servo amplifier.

The SEMC accepts motion commands and position information over the STEbus or via an RS232 link. Commands, which may be repeating sequences, are in a simple ASCII format. The SEMC can perform a complex command sequence and interrupt the main STEbus CPU when it has finished.

There are two limit switch inputs, 8 general-purpose TTL inputs which may optionally be used as resolver inputs and 8 general-purpose TTL outputs on the 50-way connector, which conforms to the Arcom standard signal-conditioning scheme. In addition this connector also carries the control voltage out and inputs for right and left limit switches, direction and stop/start signals. The SEMC and SEMC-10 occupy 3 I/O locations on the STEbus.

SEMC-10 has all the features of the but has additional motion and position commands allowing complex profiles to be generated in systems.

Power consumption:

(from STEbus): 0.8A typical at 5V