Siemens 6EP1334-1LB00 Retrofit-Ready Power Supply for SITOP

Siemens 6EP1334-1LB00 Retrofit-Ready Power Supply for SITOP Control Systems

The Siemens 6EP1334-1LB00 is a SITOP PSU100L series 24 VDC / 10 A stabilized power supply module engineered for seamless integration into existing Siemens automation architectures. As legacy SITOP PSU100 and PSU200 units reach end-of-life, the 6EP1334-1LB00 has become the preferred retrofit-ready replacement for engineers managing S7-300, S7-400, ET 200M, and ET 200SP distributed I/O stations. Its DIN-rail mounting footprint, wide-range AC input (100–240 VAC), and 24 VDC regulated output make it a direct drop-in candidate for most existing control cabinet layouts without requiring structural modification.

When planning a power supply replacement in a running production line, engineers must verify several critical parameters before committing to a swap. First, confirm that the existing cabinet’s AC feed circuit breaker rating is compatible with the 6EP1334-1LB00’s inrush current profile. Second, check the terminal block pitch on the existing wiring harness — the SITOP PSU100L uses standard 6 mm² screw terminals on both the AC input and DC output sides, which are compatible with most legacy SITOP PSU100 wiring without re-termination. Third, validate the total DC load budget: the 6EP1334-1LB00 delivers a continuous 10 A at 24 VDC, which must cover the combined draw of the CPU module (e.g., a CPU 315-2 DP or CPU 317-2 PN/DP), all SM 321/SM 322 digital I/O modules on the S7-300 rack, any IM 360/IM 361 interface modules for multi-rack expansion, and field device loads connected through the backplane.

Upgrade Compatibility Table

Retrofit Planning for Existing Automation Systems

A successful retrofit of the 6EP1334-1LB00 into an existing S7-300 or ET 200M control system begins with a thorough audit of the control cabinet. Start by documenting the current power distribution topology: identify how many 24 VDC loads are fed from the existing SITOP unit, including the S7-300 CPU rack’s PS 307 power supply slot (if a separate PS 307 5A or PS 307 10A is installed), any IM 153-1 or IM 153-2 interface modules in remote ET 200M stations, and field instruments wired directly to the 24 VDC bus.

In many legacy installations, the SITOP PSU100 powers not only the PLC backplane but also a CP 343-1 Ethernet communication processor or a CP 342-5 PROFIBUS DP master module. These communication modules have their own current draw profiles that must be factored into the load calculation. Similarly, if the cabinet includes an OP 277 or TP 277 HMI panel connected via MPI or PROFIBUS, its 24 VDC supply must be accounted for — either from the same SITOP rail or a dedicated secondary supply.

For systems using distributed I/O over PROFIBUS DP, the 6EP1334-1LB00 replacement does not affect the PROFIBUS network topology or station addressing. The DP master (typically the CPU’s integrated DP port or a CP 342-5) retains all configured slave addresses for ET 200S, ET 200M, or ET 200eco stations. However, after power restoration, engineers should verify that all DP slaves re-initialize correctly and that the CPU transitions from STOP to RUN without generating BF (Bus Fault) or SF (System Fault) LEDs. If a SIMATIC S7 STEP 7 project is available, use the Hardware Configuration tool to cross-check the configured power budget against the actual module list on each rack.

Where the existing cabinet uses a SITOP UPS module (e.g., SITOP UPS1600) for buffered power during brief outages, confirm that the 6EP1334-1LB00’s DC OK signal is correctly wired to the UPS module’s DC input monitoring terminal. This ensures the UPS activates seamlessly during mains interruptions without requiring changes to the UPS configuration parameters stored in the SITOP UPS Manager software.

For cabinets that also house a Siemens SCALANCE X208 or X216 Industrial Ethernet switch providing PROFINET connectivity to S7-1200 or S7-1500 controllers in a hybrid migration scenario, the 6EP1334-1LB00 provides sufficient current headroom to power the switch alongside the legacy S7-300 rack, simplifying the transition to a unified 24 VDC distribution bus during phased modernization projects.

Downtime Control During System Migration

Minimizing unplanned downtime during a power supply swap is the top priority for any production environment. The recommended approach is to pre-stage the 6EP1334-1LB00 on a temporary DIN rail section outside the live cabinet, perform a bench-level output voltage check and load test before installation, and schedule the physical swap during a planned maintenance window.

Before de-energizing the cabinet, use a SIMATIC S7 STEP 7 or TIA Portal project backup to save the current CPU program, including all data blocks (DBs), organization blocks (OBs), and function blocks (FBs), to an offline archive. This protects the control logic in the event of a CPU memory loss during power cycling. If the CPU uses a SIMATIC Memory Card (MMC) or SD card for program retention, verify that the card is seated correctly and that the program is stored on the card rather than only in volatile RAM.

During the swap, label all DC output wiring before disconnection to prevent mis-termination on the new unit. The 6EP1334-1LB00’s terminal layout mirrors the legacy PSU100L, so wire-for-wire reconnection is straightforward. After reconnection, restore AC power and observe the DC OK LED — a steady green indication confirms correct output voltage before the CPU is switched to RUN mode. Perform a full I/O check using the STEP 7 Variable Monitor or TIA Portal Watch Table to confirm that all SM 321 digital input modules and SM 322 digital output modules are responding correctly before releasing the line back to production.

For sites where a cold standby spare is required, the 6EP1334-1LB00 is available from stock with a lead time of 1–3 business days for most regions, supporting rapid emergency replacement scenarios with a 12-month warranty from the date of shipment.

Retrofit Support FAQ

Q1: Is the 6EP1334-1LB00 a direct replacement for the discontinued SITOP PSU100 10A unit?
Yes. The 6EP1334-1LB00 (SITOP PSU100L 24VDC/10A) is the current production successor to the legacy SITOP PSU100 10A series. It shares the same DIN rail footprint, terminal pitch, and output voltage specification, making it a direct drop-in replacement in most S7-300 and ET 200M control cabinets without wiring or mechanical modification.

Q2: Does replacing the power supply require changes to the STEP 7 or TIA Portal hardware configuration?
No. The SITOP PSU100L is a passive power module and is not represented as a configurable object in STEP 7 or TIA Portal hardware configurations. The CPU, I/O modules, and communication processors retain their existing configurations. No program download or hardware reconfiguration is required after the swap.

Q3: What pre-shipment testing is performed on the 6EP1334-1LB00?
Each unit undergoes output voltage calibration verification, load regulation testing at 50% and 100% rated current, and DC OK relay contact continuity testing before shipment. Units are shipped with original manufacturer packaging and include a test report. A 12-month warranty covers all functional defects from the date of shipment.

Q4: Can the 6EP1334-1LB00 power both the S7-300 backplane and an external HMI panel simultaneously?
Yes, provided the combined load does not exceed 10 A at 24 VDC. A typical S7-300 rack with CPU 315-2 DP, four SM modules, and a CP 343-1 draws approximately 4–6 A. An OP 277 or KTP700 Basic HMI panel adds approximately 0.5–1 A, leaving adequate headroom. Always perform a load calculation using the current consumption values from each module’s datasheet before finalizing the wiring design.

© 2026 SMARTNEXMSK. All rights reserved.
Original Source: https://smartnexmsk.com
Contact: [email protected] | +86 18259474341