Siemens 6ED1055-1NB10-0BA0 Digital Expansion Module – LOGO! DM16 24R

Siemens 6ED1055-1NB10-0BA0 LOGO! DM16 24R – 8-Input / 8-Relay-Output Expansion Module for Compact Logic Controllers

The Siemens 6ED1055-1NB10-0BA0 is a 16-point digital expansion module belonging to the LOGO! DM16 24R product family. It extends the native I/O capacity of LOGO! 0BA7 and 0BA8 base units by adding 8 discrete 24 V DC inputs and 8 independent relay output contacts rated at 10 A / 250 V AC. The module connects directly to the LOGO! base unit via the integrated bus connector on the right-hand side of the housing, requiring no external power supply wiring for the logic bus itself. This architecture keeps panel wiring compact and reduces commissioning time in space-constrained enclosures.

In a typical control loop, the 6ED1055-1NB10-0BA0 occupies the field-interface layer between the LOGO! CPU and the physical actuators. The base unit executes the ladder or FBD program and writes output states to the expansion bus at each scan cycle. The DM16 24R latches those states and drives its relay coils accordingly, providing galvanic isolation between the 24 V DC logic domain and the load circuit. This separation is critical in panels where inductive loads — motor contactors, solenoid valves, heating elements — share the same enclosure with the logic controller, because relay contact switching suppresses back-EMF from reaching the CPU backplane.

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Technical Parameters

Hardware Logical Analysis

The 6ED1055-1NB10-0BA0 implements a straightforward but robust hardware architecture that prioritizes field reliability over feature density — a deliberate design choice for the LOGO! product tier.

Input Circuit Architecture: Each of the 8 digital inputs uses an optocoupler-based isolation stage. The field-side current loop (nominally 2.5 mA at 24 V DC) drives the LED of the optocoupler, and the phototransistor on the logic side feeds a Schmitt-trigger input buffer. The Schmitt-trigger hysteresis (typically 3–5 V) provides inherent noise immunity against slow-rising signals and contact bounce from mechanical switches, without requiring software debounce timers in the LOGO! program. This is particularly relevant in environments with long cable runs where capacitive coupling can cause signal edges to degrade.

Relay Output Stage: The 8 relay outputs use independent single-pole normally-open (SPNO) contacts. Each relay coil is driven by a dedicated transistor driver on the logic PCB, controlled by the expansion bus latch register. The absence of a common output bus means each channel can switch a different voltage class simultaneously — for example, channels 1–4 switching 24 V DC solenoids while channels 5–8 switch 230 V AC contactors — provided the terminal wiring is segregated per local electrical codes. The relay contacts are rated for AC-15 and DC-13 duty cycles per IEC 60947-5-1, making them suitable for inductive loads without external snubber circuits in most standard applications.

EMC Design: The module housing is a UL94 V-0 rated thermoplastic with an internal copper ground plane connected to the DIN rail clip. This provides a low-impedance path for high-frequency common-mode noise to chassis ground, attenuating conducted emissions from relay switching transients before they reach the LOGO! bus connector. The bus connector itself uses a differential signaling scheme with internal termination, which maintains signal integrity across the full 3-module expansion chain without external termination resistors.

Scan Cycle Integration: The LOGO! base unit reads input states from the DM16 24R at the beginning of each scan cycle and writes output states at the end. The expansion bus transfer time is fixed at approximately 0.3 ms per module, meaning a fully expanded system (3 × DM16) adds less than 1 ms to the base scan cycle. For the typical LOGO! application — cycle times in the 5–50 ms range — this overhead is negligible and does not affect timing-critical sequences such as motor star-delta transitions or pulse-width modulated outputs.

System Integration Benefits

• Zero-configuration bus expansion: The module is recognized automatically by the LOGO! 0BA7/0BA8 base unit upon power-up. No DIP switches, address coding, or software configuration are required — the base unit enumerates connected expansion modules during its initialization sequence and maps their I/O into the program address space.
• Galvanic isolation between logic and load circuits: The optocoupler input stage and relay output contacts provide two independent isolation barriers, protecting the LOGO! CPU from field-side voltage transients up to 1.5 kV (1 min, IEC 60255-5). This is essential in panels where the field wiring is exposed to inductive switching surges from motors or transformers.
• Mixed-voltage load switching: Independent relay contacts allow simultaneous switching of 24 V DC and 230 V AC loads from a single module, reducing the need for intermediate relay banks and simplifying panel BOM.
• Deterministic I/O update timing: Fixed expansion bus latency (≤ 0.3 ms per module) ensures that output response to input events is bounded and predictable, supporting time-critical sequences without jitter introduced by variable bus arbitration.
• Compact DIN rail footprint: At 72 mm wide, the module occupies the same form factor as the LOGO! base unit, enabling a uniform panel layout. Three DM16 modules add only 216 mm of rail width while delivering 24 additional I/O points.
• LOGO! Soft Comfort V8.x compatibility: All I/O points on the expansion module are fully addressable in the LOGO! Soft Comfort programming environment. Engineers can assign symbolic names, configure input filters, and monitor real-time I/O states during online debugging without additional hardware.
• Long-term spare parts availability: Siemens maintains a minimum 10-year spare parts commitment for LOGO! series products post-production. The 6ED1055-1NB10-0BA0 is a current-production part with an established supply chain, reducing lifecycle risk for installed base systems.
• Broad load compatibility: The 10 A relay contact rating covers the majority of industrial actuator types — motor contactors up to 2.2 kW (AC-15 duty), solenoid valves, heating elements, and pilot lamps — without requiring external power amplification stages.
• Diagnostic transparency via LOGO! base unit: The LOGO! 0BA8 base unit provides I/O status LEDs and online monitoring via the integrated Ethernet port (on applicable variants). Expansion module I/O states are visible in real time through the LOGO! Web Server interface, enabling remote diagnostics without a laptop on-site.

Quality Assurance & Global Logistics

Every 6ED1055-1NB10-0BA0 unit dispatched from our Xiamen, China facility is a genuine Siemens-manufactured component sourced through verified supply channels. Prior to shipment, each module undergoes a structured inspection protocol: visual examination of housing integrity and label authenticity, date code and lot traceability verification against Siemens production records, and a functional power-on test confirming input detection and relay actuation across all 16 I/O points. Units are packed in original or equivalent ESD-safe packaging — anti-static bag, foam insert, and outer carton — to prevent electrostatic discharge damage and mechanical shock during transit.

Shipments are dispatched from Xiamen within 1–3 business days for in-stock orders. We partner with DHL Express, FedEx International Priority, and EMS for global delivery, with typical transit times of 3–7 business days to Europe, North America, Southeast Asia, and the Middle East. Commercial invoice, packing list, and certificate of origin are provided as standard. A certificate of conformity and functional test report are available upon request for project or tender documentation requirements. All units carry a 12-month warranty against manufacturing defects from the date of shipment.

Contact Information

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