Siemens 6EP1334-2BA20 Replacement for SITOP PSU100S

Product Overview

Siemens 6EP1334-2BA20 Replacement for SITOP PSU100S: Smooth Transition & Legacy System Upgrade

The Siemens 6EP1334-2BA20 is a proven SITOP PSU100S series 24 VDC / 10 A stabilized DIN-rail power supply widely deployed across SIMATIC S7-300, S7-400, and ET 200 distributed I/O stations. As aging control panels reach end-of-service life or original units fail in the field, sourcing a verified replacement becomes the single most critical step in minimizing unplanned downtime. TOPNLMS maintains ready stock of the 6EP1334-2BA20 to support both emergency swap-outs and planned modernization projects, with every unit pre-shipment tested and covered by a 12-month warranty.

Whether you are retiring a legacy SIMATIC S5 panel and migrating to an S7-based architecture, consolidating multiple 5 A supplies (such as the 6EP1333-2BA20) into a single higher-capacity unit, or simply replacing a failed PSU in an existing rack, the 6EP1334-2BA20 slots directly into standard 35 mm DIN rail without any bracket modification. Its wide-range AC input (85–264 VAC) accommodates both 110 V and 230 V plant environments, eliminating the need for external voltage-selection switches common in older SITOP M series supplies.

Compatibility Comparison Table

Seamless Upgrade Solutions

A power supply replacement rarely happens in isolation. In most S7-300 or ET 200M retrofit projects, the 6EP1334-2BA20 is installed alongside a coordinated set of components to ensure the entire control system transitions without wiring rework or software re-engineering.

On the controller side, the SIMATIC S7-300 CPU 314C-2 DP is the most common host CPU found in panels originally powered by the PSU100S series. Its 24 VDC backplane bus draws directly from the supply’s output terminals, and the existing 2 × 4 mm² supply cables can be reused without re-termination. Where the panel also houses a SIMATIC ET 200M IM 153-2 remote I/O head station connected via PROFIBUS DP, the same 24 VDC rail feeds the IM module’s logic supply, so a single 6EP1334-2BA20 typically covers both the CPU rack and the first ET 200M station within the same cabinet.

For panels that include analog signal conditioning, the SM 331 AI 8×13Bit and SM 332 AO 4×12Bit I/O modules draw their 24 VDC load supply from the same bus. Because the PSU100S provides a regulated, low-ripple output (≤ 150 mV p-p), sensitive analog channels maintain measurement accuracy without requiring additional signal isolators in most installations. Where legacy wiring runs exceed 30 m or cross high-noise environments, a SITOP SEL 24VDC/4×10A selective current-limiting module can be inserted downstream to protect individual branch circuits without replacing the main supply.

Communication infrastructure within the cabinet typically includes a CP 343-1 Ethernet module or a CP 342-5 PROFIBUS DP master plugged into the S7-300 rack. Both modules are powered from the same 24 VDC rail and are fully compatible with the output specification of the 6EP1334-2BA20. No firmware changes or address reassignments are required when the PSU is swapped, because the supply is transparent to the PROFIBUS or Industrial Ethernet network topology.

Where the original panel used a SITOP UPS1600 uninterruptible power supply module buffering the 24 VDC bus, the 6EP1334-2BA20 interfaces directly with the UPS1600’s charging input. The DC OK contact output on the PSU100S can be wired to the UPS module’s mains-fail input, enabling a clean handover to battery backup during grid interruptions — a feature absent on many older SITOP M predecessors.

Finally, for panels that include a SIMATIC HMI KTP700 Basic or TP1200 Comfort operator panel, the 24 VDC supply from the 6EP1334-2BA20 feeds the HMI’s power input directly. The 55 mm slim housing of the PSU100S often recovers 15–20 mm of horizontal DIN rail space compared to older 70 mm-wide units, which is frequently the margin needed to accommodate an additional SIMATIC S7-300 SM 321 DI 32×24VDC digital input module without expanding the enclosure footprint.

Retrofit Guidance FAQ

Q: Can I reuse the existing 24 VDC output wiring from the old supply?
Yes. The 6EP1334-2BA20 uses the same screw-terminal pitch and polarity convention as predecessor SITOP units. Existing 24 VDC positive and negative bus bars can be reconnected without re-labeling or re-routing, provided cable cross-sections are within the terminal’s 0.5–6 mm² acceptance range.

Q: Does replacing the PSU require any PLC program changes?
No. The 6EP1334-2BA20 is a standalone power supply with no data interface to the PLC CPU. The SIMATIC program, hardware configuration in STEP 7 or TIA Portal, and all I/O addresses remain unchanged. The only software consideration is optionally wiring the DC OK relay contact to a digital input for supply-fault diagnostics.

Q: Is the unit compatible with PROFIBUS DP and PROFINET architectures?
Yes. The PSU100S provides the 24 VDC logic supply consumed by both PROFIBUS DP nodes (e.g., ET 200M, ET 200S) and PROFINET devices (e.g., ET 200SP, ET 200MP). The supply has no protocol dependency and is agnostic to the fieldbus topology in use.

Q: What is the physical space requirement in the control cabinet?
The 6EP1334-2BA20 occupies 55 mm of DIN rail width and 90 mm depth. It is narrower than many legacy 10 A supplies, which typically required 70–80 mm. This dimensional reduction is particularly valuable in compact enclosures where rail space is constrained by existing I/O modules or terminal blocks.

Q: How do I verify the replacement unit before commissioning?
Apply AC input power with the DC output terminals open-circuit and confirm the output voltage reads 24.0–28.0 VDC using a calibrated multimeter. Then connect the load progressively (25%, 50%, 75%, 100%) while monitoring output voltage stability. The DC OK LED should illuminate green at all load levels. TOPNLMS performs this functional test on every unit prior to shipment.

Q: Can the 6EP1334-2BA20 replace a dual-channel or redundant PSU configuration?
For redundant 24 VDC bus applications, two 6EP1334-2BA20 units can be paralleled using a SITOP diode module 6EP1961-2BA00, which provides ORing diodes to prevent reverse current flow between supplies. This configuration maintains the N+1 redundancy of the original design without requiring a different PSU model.

Warranty Assurance

Every Siemens 6EP1334-2BA20 shipped by TOPNLMS is covered by a 12-month warranty from the date of delivery. Our pre-shipment inspection protocol includes output voltage verification, load regulation testing, input surge withstand check, and visual inspection of terminals and housing. Units that do not meet Siemens published specifications are quarantined and not dispatched.

In the event of a warranty claim, TOPNLMS provides a replacement unit or full refund within the warranty period. Our technical support team responds to after-sales inquiries within 1 business day and can assist with installation verification, wiring confirmation, and compatibility questions for the broader SITOP and SIMATIC ecosystem.

Stock is maintained in Xiamen, China, with standard dispatch within 1–3 business days for in-stock orders. Express air freight options are available for emergency breakdown situations. All units are shipped with original manufacturer packaging where available, or equivalent anti-static protective packaging.

For volume procurement, OEM integrators, and MRO stocking programs, please contact our sales team directly to discuss pricing, lead times, and consignment arrangements.