Siemens 6EP1333-2BA20 Replacement for SITOP PSU100S

Product Overview

Siemens 6EP1333-2BA20 Replacement for SITOP PSU100S: Smooth Transition & Legacy System Compatibility

When your existing SITOP PSU100S power supply reaches end-of-life or becomes difficult to source, the Siemens 6EP1333-2BA20 provides a proven, drop-in upgrade path that preserves your control cabinet layout, wiring topology, and downstream PLC load requirements. Designed for 24 VDC / 5 A stabilized output on a standard DIN rail footprint, this unit is a direct functional replacement for earlier SITOP series modules and is fully compatible with the 24 VDC bus architectures found in S7-300, S7-400, and ET 200 distributed I/O installations.

Industrial facilities running legacy Siemens automation platforms frequently encounter the challenge of sourcing reliable power supply replacements without triggering a full system redesign. The 6EP1333-2BA20 addresses this directly: its L+/M terminal layout mirrors the predecessor SITOP PSU100C and PSU200M wiring conventions, meaning field technicians can complete a swap in under 30 minutes without re-routing cable looms or modifying terminal block assignments. The 120–230 VAC wide-range input accepts both 50 Hz and 60 Hz grid frequencies, making it equally suitable for domestic Chinese facilities and export-destined machinery.

For plants operating Siemens S7-300 CPUs — such as the CPU 314C-2 DP or CPU 315-2 PN/DP — the 6EP1333-2BA20 delivers the stable 24 VDC rail that powers both the CPU backplane and field-side I/O. When combined with SM 321 digital input modules or SM 331 analog input modules mounted on a standard S7-300 rack, the 5 A output capacity comfortably handles mixed I/O loads without voltage droop under transient conditions. Engineers migrating from an older SITOP 6EP1333-1SL11 will find the terminal pitch, DIN rail clip geometry, and mounting depth essentially unchanged, eliminating the need for cabinet door modifications or new cable management channels.

In distributed control architectures using ET 200S or ET 200M remote I/O stations, the 6EP1333-2BA20 is frequently deployed as the local 24 VDC supply feeding IM 151-1 or IM 153-2 interface modules. Its built-in output OK signaling contact allows integration with the plant’s fault annunciation system or a SIMATIC S7 digital input card, enabling predictive maintenance workflows without additional signal conditioning hardware. For installations that also include CP 343-1 Ethernet communication processors or CP 342-5 PROFIBUS modules, the clean DC output of the 6EP1333-2BA20 ensures noise-free communication bus operation — a critical factor when migrating from older token-ring PROFIBUS segments to modern PROFINET topologies.

Retrofit projects involving SINAMICS G120 or MICROMASTER 440 variable frequency drives often require a dedicated 24 VDC control supply separate from the drive’s internal SMPS. The 6EP1333-2BA20 is well-suited for this role, providing isolated control power to the CU240E-2 control unit or BOP-2 operator panel while the main drive bus operates independently. This separation simplifies troubleshooting and allows the control circuit to remain energized during drive maintenance windows — a key operational advantage in continuous-process industries such as water treatment, chemical dosing, and conveyor logistics.

For OEMs and system integrators building new control cabinets around the Siemens TIA Portal ecosystem, the 6EP1333-2BA20 pairs naturally with SIMATIC HMI KTP700 Basic panels, S7-1200 CPUs, and LOGO! 8 logic modules in smaller machine control applications. Its compact 55 mm width allows side-by-side installation with circuit breakers, contactors, and terminal blocks from the SIRIUS 3RV and 3RT product families without exceeding standard 400 mm cabinet depth constraints.

Compatibility Comparison Table

Seamless Upgrade Solutions

A successful power supply migration rarely happens in isolation. When replacing the 6EP1333-2BA20 in an S7-300 system, engineers typically audit the entire 24 VDC distribution chain. The SITOP PSU100S 6EP1334-2BA20 (10 A variant) is a common companion upgrade for cabinets with higher aggregate I/O loads, while the SITOP buffer module 6EP4134-0GB00-0AY0 provides ride-through capability during brief mains interruptions — critical for batch process controllers where an unexpected CPU reset causes product loss.

On the field-side, SM 321 DI 32×DC 24V input modules and SM 322 DO 32×DC 24V/0.5A output modules draw their operating power directly from the 24 VDC rail supplied by this unit. Ensuring the replacement power supply is installed and verified before swapping I/O modules prevents false diagnostics during commissioning. Similarly, CP 343-1 Advanced Ethernet processors require a stable 24 VDC supply to maintain PROFINET communication with SCADA systems during the transition window — a brief power interruption here can trigger network topology reconfiguration delays of several minutes.

For cabinets that also house SINAMICS G120 drives with CU240E-2 control units, a dedicated 24 VDC / 2.5 A SITOP PSU100S 6EP1332-2BA20 is often added as a secondary supply for the drive control circuit, keeping the main 6EP1333-2BA20 dedicated to PLC and I/O loads. Signal isolators such as the SITOP SEL1400 selective current limiting module protect individual 24 VDC branch circuits, preventing a short on one I/O segment from collapsing the entire 24 VDC bus — a best practice strongly recommended during any retrofit where legacy wiring harnesses are retained.

Programming cable PC Adapter USB A2 6ES7972-0CB20-0XA0 is typically required during on-site commissioning to upload the existing S7-300 program from the CPU before the power supply swap, and to verify the program checksum after restoration. Keeping a spare MPI/PROFIBUS programming cable on-site during the retrofit window eliminates the most common cause of extended downtime during power supply replacement projects.

Retrofit Guidance FAQ

Q: Can I replace the 6EP1333-2BA20 without modifying existing wiring?
A: Yes. The L+/M terminal layout and 35 mm DIN rail clip are identical to predecessor SITOP PSU100C and PSU200M models. In standard installations, the swap is a direct mechanical and electrical replacement requiring no cable re-routing.

Q: Will the replacement affect my PROFIBUS DP communication?
A: No. The 6EP1333-2BA20 provides a clean, low-ripple 24 VDC output that meets the supply requirements of CP 342-5 and CP 343-5 PROFIBUS processors. Ensure the output OK contact is wired to a DI channel if your program monitors power supply health.

Q: What is the physical installation space requirement?
A: The unit is 55 mm wide, 125 mm tall, and 125 mm deep — identical to the predecessor 6EP1333-1SL11. No cabinet door or cable duct modifications are required in standard S7-300 cabinet layouts.

Q: How do I verify the replacement is functioning correctly before going live?
A: Measure the output voltage at the L+/M terminals under full load — it should read 24.0–24.5 VDC. Confirm the OK signaling contact closes (continuity between terminals 11 and 12) within 2 seconds of power-on. Upload and verify the CPU program checksum via STEP 7 or TIA Portal before releasing the system to production.

Q: Is the unit compatible with S7-1200 and S7-1500 systems?
A: Yes. Both platforms accept 24 VDC supply input. The 6EP1333-2BA20 is fully compatible as an external 24 VDC source for S7-1200 CPU modules and ET 200SP distributed I/O stations used in TIA Portal-based modernization projects.

Warranty Assurance

Every Siemens 6EP1333-2BA20 unit shipped by TOPNLMS is covered by a 12-month warranty from the date of shipment. Prior to dispatch, each unit undergoes output voltage verification, load regulation testing, and visual inspection to confirm it meets Siemens factory specifications. In the event of a confirmed defect within the warranty period, TOPNLMS provides a replacement unit or full refund — no lengthy RMA bureaucracy.

We maintain ready stock in Xiamen, China, with standard dispatch within 1–3 business days. Express air freight options are available for urgent plant breakdown scenarios. Our technical team is reachable at [email protected] or +86 18359293191 for pre-purchase compatibility verification, retrofit consultation, or post-sale support.

For bulk procurement, OEM integrators, and MRO stocking programs, volume pricing and extended warranty terms are available on request. All units are shipped with original manufacturer packaging where available, and include a TOPNLMS inspection certificate confirming pre-shipment test results.

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