Involves the design, construction, maintenance, troubleshooting and repair of solid state motor controls and proximity and photo sensors. U.S. and international standards for machine safety control devices, circuits, sequence and logic are introduced. Machine safety relays are examined and implemented and tested in control circuits in the lab. Machine sequence control circuits are developed using programmable logic relays (PLRs) with computer based ladder logic programming and simulation software and then connected and tested in the lab.