SIEMENS 6ES5948-3UR51 CPU 948 PLC Module | Replacement, Equivalent & Selection Guide
The SIEMENS 6ES5948-3UR51 is a high-performance CPU 948 central processing unit designed for the SIMATIC S5 programmable logic controller (PLC) platform. Engineered for large-scale industrial automation, this module delivers robust processing power, extensive memory capacity, and reliable real-time control for complex manufacturing and process environments. At Konmask.com, we help engineers and procurement teams identify the right module — original, equivalent, or compatible replacement — with full traceability and verified sourcing.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 6ES5948-3UR51 |
| Series | SIMATIC S5 |
| Module Type | CPU 948 – Central Processing Unit |
| Manufacturer | Siemens AG |
| Compatible Rack | SIMATIC S5-115U / S5-135U / S5-155U |
| Programming Language | STEP 5 (STL, LAD, CSF) |
| Communication Interface | SINEC H1 / L2 (model-dependent) |
| Operating Voltage | 24 V DC (via backplane) |
| Operating Temperature | 0 °C to +60 °C |
| Weight | Approx. 700 g |
| Dimensions (W×H×D) | Standard S5 single-width module |
| Certifications | CE, UL (original Siemens) |
Compatible Replacement & Equivalent Models
When the 6ES5948-3UR51 is unavailable or end-of-life, the following models may serve as functional equivalents or upgrades depending on your system configuration:
- 6ES5948-3UA21 – Earlier CPU 948 variant; same rack compatibility, reduced memory
- 6ES5948-3UA61 – CPU 948 with expanded program memory; direct functional equivalent
- 6ES5948-3UR21 – CPU 948 variant; compatible with S5-135U/155U racks
- 6ES5946-3UA21 – CPU 946 downgrade option for less demanding applications
- 6ES7315-2AH14-0AB0 – SIMATIC S7-300 CPU 315-2 DP; modern migration path with PROFIBUS DP
- 6ES7317-2AK14-0AB0 – SIMATIC S7-300 CPU 317-2 DP; recommended for full S5→S7 migration
⚠ Note: S7-series replacements require hardware migration and STEP 7 reprogramming. Always consult your system integrator before substitution.
Why Choose the Original Model
- Drop-in compatibility — No rack modification required for S5-135U/155U systems
- STEP 5 native execution — Runs existing programs without conversion overhead
- Proven field reliability — Decades of deployment in heavy industry worldwide
- Reduced downtime risk — Identical firmware behavior eliminates re-validation cycles
- Lower total cost — Avoids full system migration costs when S5 infrastructure is still operational
Typical Applications
- Automotive body-in-white and powertrain assembly lines
- Chemical and petrochemical process control systems
- Steel mill rolling and continuous casting automation
- Power generation and substation control
- Water treatment and municipal infrastructure SCADA
- Pharmaceutical batch processing and CIP systems
- Paper and pulp mill drive coordination
System Compatibility
- Racks: SIMATIC S5-135U (6ES5135-3KB21), S5-155U (6ES5155-3AA11)
- Power Supplies: 6ES5955-3LC41, 6ES5955-3LF41
- Memory Modules: 6ES5374-1FH21 (RAM), 6ES5375-1LA21 (EPROM)
- I/O Modules: Full range of S5 digital/analog I/O (6ES5 series)
- Communication: 6ES5734-1BD20 (CP 5431 FMS/DP), 6ES5521-8MA22 (CP 521 SI)
- Programming: STEP 5 v7.x via PG 740/760 or PC adapter (6ES5734-1BD20)
Selection Guide
| Scenario | Recommended Action |
|---|---|
| Identical replacement, S5 system retained | Order 6ES5948-3UR51 directly |
| Need more program memory, keep S5 | Consider 6ES5948-3UA61 |
| Migrating to modern platform | Evaluate S7-300 CPU 315-2 DP or CPU 317-2 DP |
| Budget-constrained, less I/O required | Downgrade to CPU 946 (6ES5946-3UA21) |
| Uncertain about compatibility | Contact Konmask.com for free selection support |
Quality Assurance & Sourcing
- Verified Origin: Sourced from authorized distributors and certified industrial surplus channels
- Inspection Protocol: Visual inspection → functional power-on test → firmware version verification → packaging integrity check
- Traceability: Each unit ships with sourcing documentation and inspection record
- Warranty: 12-month replacement warranty against manufacturing defects
- Anti-Counterfeit: Siemens holographic label and date-code verification on every unit
How to Order
- Confirm your rack model and current CPU firmware version
- Specify quantity and required delivery timeline
- Request a quotation via support@konmask.com or WhatsApp +0086 19859288691
- Receive proforma invoice with lead time confirmation
- Payment → inspection report issued → shipment with tracking
We support DHL / FedEx / UPS Express and sea freight for bulk orders. Export documentation (CO, packing list, commercial invoice) provided for all international shipments.
Replacement & Compatibility FAQ
Q: Can I replace 6ES5948-3UR51 with 6ES5948-3UR21 directly?
A: Yes, both are CPU 948 variants with the same rack footprint. Verify memory size and firmware version match your application requirements before swapping.
Q: Is migration from S5 to S7 necessary?
A: Not immediately. If your S5 system is stable and spare parts are available, maintaining the original platform is often more cost-effective. Migration becomes advisable when spare parts are critically scarce or when new functionality (PROFINET, safety) is required.
Q: Do you supply tested or untested units?
A: All units from Konmask.com are power-on tested and functionally verified before shipment. Untested units are not offered.
Q: What is the lead time for 6ES5948-3UR51?
A: Typically 3–7 business days for in-stock units. Contact us for real-time availability confirmation.
Q: Can you provide a certificate of conformity?
A: Yes. A sourcing declaration and inspection certificate are included with every shipment upon request.
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Original Source: https://Konmask.com
Contact: support@konmask.com | +0086 19859288691
