Siemens 6ES7590-1AC40-0AA0 Mounting Rail – SIMATIC S7-1500

Siemens 6ES7590-1AC40-0AA0 — 482 mm Mounting Rail for SIMATIC S7-1500 and ET 200MP Systems

The 6ES7590-1AC40-0AA0 is a 482 mm (19-inch rack-equivalent) mounting rail manufactured by Siemens AG for exclusive use with the SIMATIC S7-1500 programmable logic controller platform and the ET 200MP distributed I/O system. Within any S7-1500 control cabinet architecture, the mounting rail is the mechanical and electrical backbone: it provides the rigid substrate onto which CPU modules, interface modules, I/O modules, and power supply modules are snapped and locked, while simultaneously forming the low-impedance ground reference plane that underpins the system’s EMC performance.

Unlike generic DIN rails, the 6ES7590-1AC40-0AA0 is precision-machined to Siemens’ dimensional tolerances, ensuring that the backplane bus connectors on each module seat with consistent contact force across the full 482 mm span. This dimensional consistency is not cosmetic — it directly determines the electrical integrity of the U-connector backplane bus that carries 24 V DC logic power, the local bus communication signals, and the PE (protective earth) bonding path between modules. Any deviation in rail geometry introduces micro-gaps at the bus connector interface, which under vibration can produce intermittent bus faults that are notoriously difficult to diagnose in the field.

The 482 mm length corresponds to a standard 19-inch rack width, making this rail the preferred choice for installations inside 19-inch industrial enclosures and control panels where space allocation follows IEC 60297 cabinet standards. For wider configurations or extended I/O counts, Siemens offers complementary rail lengths (160 mm, 245 mm, 830 mm, 2000 mm); the 6ES7590-1AC40-0AA0 occupies the mid-range, accommodating a CPU plus up to approximately 26 I/O or function modules depending on module widths.

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Technical Parameters

Hardware Logical Analysis

The 6ES7590-1AC40-0AA0 is not a passive mechanical component in the conventional sense. Its design integrates three distinct engineering functions that directly affect system reliability:

1. Backplane Bus Mechanical Interface Precision
The S7-1500 backplane bus uses a U-connector system where each module’s right-side bus connector mates with the left-side connector of the adjacent module. The mounting rail’s slot geometry controls the lateral and vertical positioning of each module to within ±0.1 mm. This tolerance stack-up management ensures that across a fully populated 482 mm rail, the cumulative positional error at the last module remains within the bus connector’s rated contact engagement depth. Exceeding this tolerance — as occurs with non-genuine or dimensionally non-compliant rails — results in partial connector engagement, elevated contact resistance, and susceptibility to bus communication errors under thermal cycling or mechanical vibration.

2. EMC Ground Reference Plane
The galvanized steel rail with chromated surface treatment provides a continuous, low-impedance ground plane. When modules are mounted, their PE spring contacts make direct metal-to-metal contact with the rail surface. This creates a star-topology PE bonding arrangement where each module’s chassis ground is independently referenced to the rail, rather than daisy-chained through adjacent modules. The result is a ground reference impedance typically below 0.1 Ω between any two modules on the rail — a critical parameter for suppressing common-mode noise on analog I/O channels and for meeting the IEC 61000-4 series EMC immunity requirements that S7-1500 systems are certified to.

3. Thermal Expansion Management
The 482 mm steel rail has a coefficient of thermal expansion (CTE) of approximately 12 × 10⁻⁶ /°C. Over a 60 °C operational temperature range, this produces a total rail length change of approximately 0.35 mm. The module mounting slots are designed with controlled clearance to accommodate this expansion without inducing lateral stress on the bus connectors. This thermal management is particularly relevant in outdoor enclosures or process environments with significant ambient temperature swings, where inferior rail materials with mismatched CTE values can cause progressive connector wear over thousands of thermal cycles.

System Integration Benefits

• Direct TIA Portal Recognition: When modules are mounted on a genuine 6ES7590-1AC40-0AA0 rail and powered, TIA Portal’s hardware configuration tool automatically detects the physical slot positions via the backplane bus. Non-genuine rails that cause bus connector misalignment can produce phantom slot detection errors that require manual hardware configuration overrides.
• Deterministic Bus Cycle Time Preservation: The S7-1500 local bus operates at a fixed cycle time that is a function of the number of modules and their data widths. Mechanical integrity of the rail-to-module interface ensures that bus cycle time remains within the CPU’s configured tolerance, preventing watchdog-triggered CPU stops in time-critical applications.
• Simplified Cabinet Layout Planning: The 482 mm length maps directly to standard 19-inch rack units, enabling engineers to use standard cabinet layout tools (e.g., EPLAN, WSCAD) without custom rail dimension entries. This reduces engineering hours during the cabinet design phase.
• Integrated PE Bonding Eliminates External Grounding Straps: Because the rail provides the PE reference for all mounted modules, no additional inter-module grounding straps are required. This reduces wiring complexity, eliminates a potential source of ground loop impedance variation, and simplifies cabinet inspection during commissioning.
• Scalable Expansion Path: A system initially populated with a CPU and four I/O modules on a 482 mm rail can be expanded by adding modules up to the rail’s physical capacity without any rail replacement. This preserves the initial cabinet layout investment and avoids downtime associated with rail changeouts.
• Compatibility with S7-1500 Redundancy Configurations: In S7-1500R/H redundant CPU configurations, both the active and standby CPU assemblies require identical rail geometry to ensure that the synchronization module’s backplane bus connections are mechanically equivalent. The 6ES7590-1AC40-0AA0 is the specified rail for standard-width redundant configurations.
• Vibration and Shock Resistance: The pre-drilled M6 mounting holes allow the rail to be bolted directly to the cabinet backplate with defined torque values, achieving a mechanically rigid assembly that meets IEC 60068-2-6 (vibration) and IEC 60068-2-27 (shock) test requirements applicable to the S7-1500 system.
• Reduced Commissioning Risk: Using the OEM-specified rail eliminates a variable from the commissioning process. When a system is built to Siemens’ bill of materials, any fault that arises during commissioning can be systematically attributed to configuration, wiring, or software — not to mechanical infrastructure uncertainty.

Quality Assurance & Global Logistics

Every 6ES7590-1AC40-0AA0 unit dispatched from our Xiamen, China facility is a genuine Siemens AG product, sourced through verified industrial distribution channels with full procurement traceability. We do not handle refurbished, reconditioned, or grey-market stock. Each unit is inspected upon receipt for label authenticity (including Siemens holographic security labels where applicable), dimensional integrity, and surface condition before being entered into our inventory system.

Packaging follows Siemens’ original carton specifications with anti-static inner wrap where required. Export documentation — including commercial invoice, packing list, and certificate of origin — is prepared for every international shipment. HS Code 8538.90 is applied for customs classification. We work with DHL Express, FedEx International Priority, and SF Express International to provide transit times of 3–7 business days to most destinations in Europe, Southeast Asia, the Middle East, and the Americas. For time-critical orders, same-day dispatch is available for orders confirmed before 14:00 CST.

All units are covered by a 12-month warranty from the dispatch date. In the event of a verified manufacturing defect, we arrange replacement or credit without requiring the customer to engage Siemens’ regional service network directly — reducing resolution time for procurement and maintenance teams.

Contact Information

📧 Email: [email protected]
💬 WhatsApp: +86 18359268345
🌐 Web: siemensplc.com
📍 Location: Xiamen, China
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