The PCL501 programmable controller is an economical single-axis step motor controller containing 2 Kbytes of non-volatile stored programming memory. It provides flexible, independent control of step motors with clock and direction outputs from computers or machine controllers with a serial port. It is also capable of stand-alone operation making it an embedded machine controller. The easy to use Windows software, SMC50WIN, can be used to directly control motion and to program the controller. The PCL501 programmable controller also has the ability for real time functions. A "Direct Mode" is used to directly control motion for real time movements through serial communication. The PCL501 programmable controller has 18 commands which are easy-to-remember for direct movement of a stepper motor. The controller communicates via RS485 communication. Up to 32 units can be networked from one communications port on a PC or PLC (Programmable Logic Controller). The PCL501 programmable controller has 2 programmable open drain outputs and 4 TTL compatible inputs. It can be powered with DC (5-24VDC) or AC (8-16VAC) voltages. It's compact size and mounting provisions make it simple to install.