This paper describes a program for the simulation of the control logic and system dynamics of a robot arm having three Cartesian axes of motion plus two rotational axes of the wrist. The program was written in the C language and includes a fourth-order Runge-Kutta algorithm for the integration of the nonlinear differential equations for the individual axes. Validation of the program operation and evaluation of the many system parameters are also discussed. The simulated motion is compared and adjusted to fit experimental data on the actual arm motion. The results indicate that the simulation can be a useful and safe means for off-line testing of system changes and new control schemes.