The Siemens 6AG1123-2GA03-2AX0 is a serial-interface HMI designed for legacy Siemens automation networks. It supports MPI and PROFIBUS as the primary fieldbuses, with MODBUS RTU available for interoperation with Modicon controllers. No Ethernet, PROFINET, or USB ports are present, so this unit targets panels that are already on a PROFIBUS backbone or that need a simple serial terminal for S7-1200 or S7-1500 PLCs via the integrated MPI. The temperature range spans -20 to 60 °C, making it usable in unconditioned enclosures or outdoor-rated cabinets. Rear ingress protection is IP20, so a proper IP54+ enclosure is required if the panel sits in a washdown or dusty area.
Connectivity constraints
No CAN, CSV, DCP, IRT, MRP, DHCP, HTML, HTTP, LLDP, SNMP, or TCP/IP are supported. This reduces network setup complexity but also means the HMI cannot participate in industrial Ethernet diagnostics or web-based monitoring.
Physical interface and enclosure
The unit is built into a plastic housing with a rear IP20 rating. It includes physical buttons, a buzzer, and indicator icons. A flash memory stores the runtime screens. There are no sliders, speakers, or aluminum bezels — the interface is tactile and audible, suited for operator input in noisy environments.