Siemens SITOP Power Supply Modules: 6EP1332-1LB00

Technical Dossier

Product Details And Specifications

Siemens SITOP Series: Comprehensive Module Range and Technical Overview

The Siemens SITOP power supply series is one of the most widely deployed 24 VDC industrial power supply families in global heavy industry. Installed across petrochemical complexes, nuclear power auxiliary systems, offshore platforms, and continuous-process refineries, SITOP units serve as the regulated DC backbone for SIMATIC S7 PLCs, distributed I/O racks, HMI panels, and field instrumentation. Their DIN-rail form factor, wide-range AC input, and integrated diagnostics make them the reference standard for panel builders and system integrators operating under IEC 60364 and NEC Class 2 requirements. The 6EP1332-1LB00 is a 1-phase, 24 VDC / 5 A unit from the SITOP smart line, designed for compact control cabinet installations where space and budget constraints apply without compromising output stability.

The Evolution of SITOP Architecture

The SITOP product family was introduced by Siemens in the early 1990s as a successor to discrete transformer-rectifier-filter assemblies. The first generation, marketed under the SITOP power designation, offered basic single-phase rectification with limited diagnostic output. By the mid-1990s, the SITOP smart line introduced active power factor correction (PFC) and a universal input range of 85–264 VAC, eliminating the need for voltage selector switches in global deployments.

The 2000s saw the introduction of the SITOP modular family, which separated the base unit from plug-in expansion modules for redundancy (6EP1961-2BA00), buffer (6EP1931-2DC42), and load distribution. This architecture allowed system designers to build N+1 redundant 24 VDC buses without external diode ORing circuits. The SITOP PSU8200 and PSU6200 lines, introduced in the 2010s, added PROFINET/PROFIBUS diagnostic interfaces, enabling integration into SIMATIC WinCC and TIA Portal alarm management.

Compatibility considerations: SITOP smart units (6EP13xx-1LBxx) use standard 24 VDC output and are electrically compatible with any SIMATIC S5, S7-300, S7-400, or S7-1500 load. However, the diagnostic signaling contact (DC OK relay) pinout differs between smart and modular generations. Panel retrofits must verify terminal assignments before substitution.

SITOP Full Catalog & Functionalities (SKU List)

The following SKUs represent verified, commonly stocked models across the SITOP smart, modular, and PSU8200 product lines. Each entry reflects a distinct electrical specification or form factor.

6EP1332-1LB00: SITOP smart, 1-phase, 24 VDC / 5 A, DIN-rail, 120 W output capacity.
6EP1333-1LB00: SITOP smart, 1-phase, 24 VDC / 10 A, DIN-rail, 240 W, standard workhorse for S7-300 racks.
6EP1334-1LB00: SITOP smart, 1-phase, 24 VDC / 20 A, DIN-rail, 480 W, high-current panel supply.
6EP1336-1LB00: SITOP smart, 1-phase, 24 VDC / 40 A, DIN-rail, 960 W, large-scale distributed I/O buses.
6EP1331-1LB00: SITOP smart, 1-phase, 24 VDC / 2.5 A, DIN-rail, 60 W, compact auxiliary supply.
6EP1961-2BA00: SITOP modular redundancy module, 24 VDC, parallel operation of two PSUs with load sharing.
6EP1931-2DC42: SITOP buffer module, 24 VDC / 40 A, capacitor-based ride-through up to 200 ms.
6EP1935-6MD21: SITOP UPS1600, 24 VDC / 20 A, battery-backed UPS with USB/PROFINET interface.
6EP3333-8SB00-0AY0: SITOP PSU8200, 1-phase, 24 VDC / 10 A, PROFINET diagnostics, TIA Portal integration.
6EP3334-8SB00-0AY0: SITOP PSU8200, 1-phase, 24 VDC / 20 A, PROFINET diagnostics, wide-range input.
6EP3336-8SB00-0AY0: SITOP PSU8200, 1-phase, 24 VDC / 40 A, PROFINET diagnostics, high-current bus supply.
6EP3437-8SB00-0AY0: SITOP PSU8200, 3-phase, 24 VDC / 40 A, three-phase input for industrial MCC panels.
6EP4134-0GB00-0AY0: SITOP PSU6200, 1-phase, 24 VDC / 10 A, entry-level with DC OK contact.
6EP4136-0GB00-0AY0: SITOP PSU6200, 1-phase, 24 VDC / 20 A, cost-optimized mid-range supply.
6EP1437-3BA00: SITOP modular, 3-phase, 24 VDC / 40 A, for high-availability process control panels.
6EP1436-3BA00: SITOP modular, 3-phase, 24 VDC / 20 A, standard three-phase DIN-rail unit.
6EP1931-2EC41: SITOP selectivity module, 4-channel, 24 VDC, electronic circuit breaker for load distribution.

Sourcing Hard-to-Find & Obsolete SITOP Parts

Several SITOP smart models, including the 6EP1332-1LB00 and adjacent 6EP1331/6EP1334 variants, have reached end-of-production status under Siemens lifecycle phase 4 (phase-out). OEM replacement with PSU8200 equivalents is the factory-recommended path, but this requires panel rewiring and TIA Portal reconfiguration — a non-trivial cost in live production environments.

DriveKNMS maintains a dedicated inventory of tested surplus and refurbished SITOP smart units to support lifecycle extension for facilities that cannot execute a full panel retrofit. Our sourcing network covers decommissioned European and Asian process plants, providing access to low-hour units with full electrical verification. For critical spares programs, we offer consignment stock agreements and lead-time guarantees for SITOP smart, modular, and early PSU8200 models.

Quality Control for the SITOP Range

SITOP power supplies present specific test challenges due to their active PFC front-end, soft-start circuitry, and DC OK relay output. DriveKNMS applies the following verification protocol to all SITOP units processed through our facility:

Input range verification: Units are energized across the full rated input range (85 VAC to 264 VAC) to confirm PFC stage integrity and inrush current limiting. Output regulation test: Output voltage is measured under 0%, 50%, and 100% resistive load using calibrated electronic loads. Ripple and noise are measured per EN 61204-3. DC OK contact test: The signaling relay is verified for correct pull-in voltage threshold and contact continuity under rated load. Thermal cycling: Units are operated at 100% load for a minimum of 2 hours in a controlled 40°C ambient environment to screen latent capacitor and MOSFET failures. Isolation test: Input-to-output and input-to-PE isolation is verified at 1500 VAC / 1 minute per IEC 62368-1.

© 2026 DriveKNMS. All trademarks belong to their respective owners. Specifications are for reference only and subject to change without notice. Verify all parameters against official documentation before installation.