Description
1. Unboxing & Physical Snapshot (Dynamic List)
- Model & Brand: Siemens 6ES5944-7UB21 (SIMATIC S5 CPU 944 Central Processing Unit)
- Physical Dimensions: Approximately 290mm x 230mm x 40mm (W x H x D)
- Estimated Shipping Weight: 1.1 kg (boxed with molded static-dissipative foam cushioning)
- What’s in the Box: 1x 6ES5944-7UB21 CPU module sealed inside an original metal-out anti-static ESD shielding bag, mode selector key, battery compartment cover, and original OEM compliance documentation.
2. Product Introduction (Structure C: Compliance Hook)
Regulatory compliance governs every decision inside high-consequence process environments, requiring hardware certified to strict international safety thresholds. Operating critical manufacturing lines demands central processing units carrying transparent documentation and traceable manufacturing histories to pass independent safety audits.
The Siemens 6ES5944-7UB21 satisfies these rigorous verification protocols through precise galvanic isolation boundaries and documented thermal limits. (We always inspect the physical laser-etched serial codes against the accompanying Certificate of Conformance during incoming receiving inspections.)
3. Core Technical Specifications
| Parameter | Value |
| Processor Type | CPU 944 central processing unit for SIMATIC S5-115U / S5-135U automation systems |
| Backplane Power Draw | Max 2.2 A at 5V DC supply |
| Power Dissipation | 11.5 W under full computational load |
| Memory Capacity | Integrated RAM with battery backup support (EPROM submodule compatible) |
| Processing Speed | High-performance bit/word processing for complex control loops |
| Communication Interface | AS511 programming port and integrated bus interfaces |
| Operating Temperature | 0°C to +55°C (natural convection cooling) |
| Storage Temperature | -40°C to +70°C |
| Mounting Standard | Dedicated CPU slot in SIMATIC S5 central subrack |
4. Global Compliance & Industry Certifications
Auditors demand verifiable documentation confirming that legacy system components comply with rigorous electrical safety mandates before plants resume operation.
- Expected Certifications: CE Mark, UL/cUL Listed (Industrial Control Equipment), CSA certification, and VDE conformity.
- Compliance Significance: UL listings verify that internal processor board spacing and insulating materials prevent dielectric breakdown under surge conditions. (Class I Div 2 ratings ensure zero risk of spark ignition within classified hazardous plant sectors.) Verify specific lot certifications with OEM documentation before closing out compliance audits.
5. Long-Term Storage & Asset Preservation Guide
Warehouse storage destroys unprotected electronics if humidity and electrostatic hazards go unmanaged. Keep this asset safe:
- Store the CPU module sealed tightly inside its original metal-out anti-static (ESD) shielding bag to block atmospheric moisture and static discharge from damaging sensitive microprocessors.
- Maintain warehouse relative humidity strictly below 60% to prevent micro-corrosion on the high-density backplane connector fingers.
- Disconnect or remove the backup lithium battery if prolonged storage exceeds twelve months to prevent acid leakage from damaging the circuit board traces.
6. Physical Installation Prerequisites
Proper mechanical placement guarantees longevity and prevents localized overheating inside the heavy-duty cabinet enclosure.
- Convection Clearance: Leave at least 60mm of open space above and below the CPU chassis to permit proper vertical airflow across the heat-generating components.
- Grounding Protocol: Bond the integrated module shielding frame directly to the subrack grounding busbar using star lock washers to suppress electromagnetic interference (EMI).
7. Buyer’s FAQ (Logistics & Compliance Focus)
Q: Which Harmonized System (HS) code applies to international customs clearance for the 6ES5944-7UB21?
A: This central processing unit typically clears under HS code 8537.10 or 8538.90, but importers should confirm final classification with their broker according to local destination rules.
Q: Does this surplus unit come with pre-loaded system firmware?
A: New surplus hardware ships with standard factory system firmware burned onto onboard ROM; engineering teams must download the compiled S5 user program file using STEP 5 programming software prior to deployment.
Q: How does the declared Country of Origin (COO) influence international shipping paperwork?
A: The COO—typically Germany for this heritage manufacturing line—governs preferential duty rates under international trade agreements, making a verified certificate of origin essential for seamless customs processing.
