The HMI520 operator interface terminal (OIT) for machine control systems is touted as a 5.7" high-resolution graphic display that is easy to program. Two versions of this industrial-grade system are available: color, and monochrome. Both use a 166-MHz 32-bit RISC microprocessor along with 1 MB of flash PROM to store project information and 4 MB of DRAM for data storage during operation. The color version of the HMI520 has a 320 x 240 STN 256-color display. The monochrome version has a blue-mode display having the same resolution and is capable of displaying four shades. Both models use a four-wire analog resistive touch-screen that allows multiple objects to be controlled by one key stroke. The OITs require 24 vdc for input voltage and have two communications ports: an RS232/485 for PLC communications, and an RS-232 programming port. The units can display up to 255 screens, and there is virtually no limitation to the amount of data that can be monitored on each screen. Each screen can display up to six "pop-up" windows simultaneously. The configuration software also includes an on-line simulator mode, which allows the programmer to make edits to the project and test them by simulating the operation of the OIT on the computer. This greatly minimizes the amount of development time required, since the user need not wait for lengthy downloads. The HMI520 measures just 5.9"H x 8"W x 2.85"D. It is CE marked for electrical noise immunity in industrial environments. The HMI520 monochrome list price is $995; the color version is $1295.