This paper describes the design and implementation of a low-cost robot control system based on a Programmable Logic Controller (PLC). The robot is a 2-DoF (Degrees of Freedom) purely translational mechanism, which has potential application in food and electronics industry for high speed pick-and-place operation. Combined with a conveyor belt, it can make 3-DoF purely translation motion. In this paper, the inverse kinematics, forward kinematics, singularity, and workspace analysis are presented. The control system architecture and software design is also introduced. The prototype is exhibited at last.