Models and screen options OP320A available in blue screen and yellow screen OP320AS available in blue screen and yellow screen MD204 available in blue screen, yellow screen, and green screen Difference between OP320A and OP320AS: OP320A provides builtin RS232 and RS422 communication ports. OP320AS provides RS232 and RS485 communication ports. Key benefits Immediate HMI access to PLC registers and relays for monitoring and control without changing PLC programs. View and modify values as text or indicator lights. Wide compatibility with PLCs and intelligent controllers that offer serial communication ports, simplifying integration. Robust hardware and stable firmware for reliable operation in industrial environments. Compact footprint and IP65 front protection for easy panel mounting and use on production equipment. Main features Display: 3.7 inch STN, L C D type. Display area 101 x 36 mm. LCM types: blue, yellow, and green screen options. Blue screen shows white text on a blue background. Backlight: long life white LED backlight for consistent visibility. Brightness: 60 cd/m2. Contrast adjustable with potentiometer. CPU and memory: 8bit processor with 64 KB flash ROM. Power: 12 to 24 V DC, +/10%. Typical current less than 150 mA at 24 V DC. Communication: COM1 supports PC RS232 and PLC connections. OP320A includes RS232 and RS422. OP320AS includes RS232 and RS485. Ports and interfaces: no print port, no real time clock, no recipe memory. Buttons: 20 definable function keys for custom operator controls. Materials and build: ABS housing material, natural air cooling, front panel rated to IP65. Reliability and safety tests: withstand voltage 500 VAC for 1 minute, antiinterference test 1500 V peaktopeak, insulation resistance greater than 10 megaohm at 500 V DC. Lifespan and environment: LCM life approximately 50,000 hours at 25 C +/ 2 C and 65% +/ 10% humidity. Operating temperature 0 to 50 C. Storage temperature 20 to 70 C. Operating humidity 20% to 90% noncondensing. Mechanical: overall dimensions 172 x 95 x 30 mm. Cutout opening 165 x 86 mm. Weight 0.3 kg. Performance: allow power interruption recovery in less than 20 ms. How it solves common problems Reduces engineering effort by allowing communication protocol and screen data to be downloaded to the display without requiring modification of PLC communication programs. Provides clear local visibility and control of PLC internal registers and relay status for fast troubleshooting and onsite adjustments. Small footprint and IP65 front fit into standard control panels while protecting the interface from dust and splashes. Typical applications Factory automation control panels for machine tools, conveyors, and assembly equipment where a compact, serialcommunicating HMI is required. Packaging and processing lines that require immediate operator interaction with PLC registers for setup changes and status feedback. Test rigs and laboratory controllers where a simple, rugged operator interface is needed to monitor and change process variables. Technical summary Display size 3.7 inch STN, visible area 101 x 36 mm Brightness 60 cd/m2, adjustable contrast Power 12 to 24 V DC +/10%, <150 mA at 24 V DC CPU 8bit, memory 64 KB flash ROM Communication RS232 standard; RS422 on OP320A; RS485 on OP320AS Buttons 20 programmable keys Protection IP65 front panel, ABS housing Dimensions 172 x 95 x 30 mm, cutout 165 x 86 mm, weight 0.3 kg Operating range 0 to 50 C, storage 20 to 70 C, humidity 20% to 90% noncondensing No real time clock, no recipe memory, no print port Backlight long life white LEDs, estimated LCM life 50,000 hours at 25 C Ordering guidance Choose OP320A for RS232 and RS422 communication. Choose OP320AS for RS232 and RS485 communication. Select MD204 if the MD204 feature set and color options meet application needs. Select screen color according to visibility preference: blue, yellow, or green.