The Siemens 6AG1688-3XY38-2AX0 is a SIPLUS HMI design empty front in KP8 format — essentially a ruggedized enclosure bezel and housing for building a custom operator panel. It carries conformal coating and is based on the standard 6AV3688-3XY38-3AX0, extended for the -40…+60 °C operating range (storage to +80 °C). This is not a display or a controller; it is the mechanical front end that accepts up to five standard 22.5 mm command devices (pushbuttons, selector switches, pilot lights) and integrates into the Siemens pro device extension units. Rated IP65 at the front and IP20 at the rear, it withstands washdown splashes from the panel face while the rear remains protected inside the enclosure. The aluminum housing (no plastic, no stainless steel) gives it a solid feel and good thermal conduction for the -40…+80 °C storage span.
The -40 °C minimum and +80 °C maximum storage range cover freezer-to-oven extremes, but the operating limits depend on mounting orientation. For vertical installation the maximum ambient is 60 °C; at maximum tilt angle (180° to the front/rear) it is also 60 °C. The -40 °C minimum holds for both orientations. Startup is rated from -25 °C. These numbers mean the unit can live in a refrigerated warehouse or a hot foundry control cabinet — as long as the panel interior stays within the 60 °C ceiling during operation. The conformal coating protects the electronics against condensation and corrosive atmospheres — a common requirement in food processing, chemical dosing, or outdoor kiosks where the panel interior sees humidity swings.
Safety function suitability
The part is marked suitable for safety functions, specifically for installation of emergency stop devices. This means the mechanical mounting and the IP65 front face meet the ingress and structural requirements for a safety-rated operator station. It does not itself contain safety logic — that comes from the e-stop pushbutton and the safety relay or PLC that reads it. The empty front gives you a certified mechanical platform to build a guarded operator interface.
Mounting and mechanical integration
Front mounting only — no DIN rail, no rack, no wall-mount option. The cutout in the mounting plate is 68 mm wide by 129 mm high, with a plate thickness of 2 to 6 mm. The housing front measures 155 mm high by 98 mm wide, overall depth 49 mm. Clamp terminals handle the wiring. Portrait and landscape orientations are both supported, and mounting position is unrestricted (any). The five slots accept standard 22.5 mm operator controls — pushbuttons, selector switches, key switches, pilot lights.