The Siemens 6ES7401-1DA01-0AA1 is a SIMATIC PCS 7 CR3 XTR central rack for the S7-400 platform, providing 4 slots for I/O and processor modules in a compact 130 mm wide by 290 mm tall chassis. This is the XTR variant, meaning it ships with conformal coating per ISA-S71.04 severity levels G1, G2, and G3, and is rated for an extended operating temperature range of 0 °C to 70 °C — suitable for environments with corrosive gases, humidity, or thermal cycling that would kill a standard rack. The rack includes a P bus and communication bus backbone, so it accepts all standard S7-400 modules and handles backplane data exchange without an external bus connector.
At 27.5 mm deep and 750 g, this rack mounts directly into a standard S7-400 subrack or panel cutout — no DIN rail, it bolts in. The 4-slot form factor is the smallest in the CR3 XTR line, so it fits tight enclosures where a 9-slot rack (like the 6ES7400-1JA11-0AA1 at 257.5 mm wide) won't. The conformal coating means you can install this in a panel that sees occasional washdown overspray or chemical vapors — think food processing, wastewater, or chemical dosing skids — without a separate sealed enclosure.
Approvals include UL, CE, UKCA, FM, KC, EAC, RCM, and CCC — so it clears panels destined for North America, Europe, the UK, South Korea, Russia, Australia, and China without a separate certification run.