Description
Product Introduction & Engineering Value
The Siemens 6ES7408-1TA01-0XA0 is a 24 VDC fan subassembly designed for SIMATIC S7-400 automation racks with 18 module slots. It provides controlled airflow through the PLC rack area, helping maintain acceptable operating temperatures for CPU, communication, and signal modules installed in larger S7-400 systems.
Cooling hardware is often ignored until thermal alarms appear or PLC reliability begins to degrade. In large control cabinets, a failed fan assembly can shorten module life, increase cabinet temperature, and create intermittent faults that are difficult to reproduce. Maintaining a tested replacement fan unit is a practical spare strategy for long-running S7-400 installations.
Technical Specifications
| Specification | Details |
|---|---|
| Manufacturer | Siemens |
| Product Family | SIMATIC S7-400 |
| Part Number | 6ES7408-1TA01-0XA0 |
| Module Type | Fan Subassembly |
| Rack Size | 18-slot S7-400 rack |
| Supply Voltage | 24 VDC |
| Permissible Voltage Range | 19.2 to 30 VDC |
| Starting Current | Approx. 0.9 A at 24 VDC |
| Rated Current | Approx. 450 mA |
| Power Consumption | Approx. 12 W with fan operating |
| Fan Lifetime | Approx. 70,000 hours at 40°C |
| Relay Contact Rating | 24 VDC, max. 200 mA |
| Fuse | 1.0 AT, 5 × 20 mm cartridge fuse |
| Dimensions (W × H × D) | 482.5 × 109.5 × 235 mm |
| Weight | Approx. 1.6 kg |
| Installation | S7-400 rack/cabinet mounting |
Field Application & The “Trench” Experience
A chemical processing facility operating an older Siemens S7-400 control platform began experiencing intermittent PLC cabinet temperature warnings during summer operation. The CPU and communication modules showed no hardware faults, but several diagnostic events appeared during periods of high ambient temperature.
The maintenance team initially investigated the cabinet HVAC system. Air conditioning performance was normal. During inspection of the PLC rack, technicians found that the existing fan assembly was running inconsistently and airflow across the rack was reduced.
A replacement 6ES7408-1TA01-0XA0 fan subassembly was installed. After startup, fan status monitoring was verified, cabinet temperature returned to normal levels, and the S7-400 system resumed stable operation.
The field lesson: cooling failures rarely announce themselves as “fan problems.” They often appear as unexplained PLC resets, communication interruptions, or shortened hardware life.
Typical application scenarios:
- S7-400 CPU cabinets in continuous process plants
- Large rack systems with multiple communication modules
- Power generation control cabinets
- Chemical and manufacturing PLC installations requiring forced cooling
6ES7408-1TA01-0XA0 S7-400
6ES7408-1TA01-0XA0 S7-400
Transparency SOP: QA & Testing
Cooling assemblies require mechanical and electrical inspection before entering critical spare inventory.
Testing workflow:
1. Identification Verification
- Confirm Siemens SIMATIC label.
- Verify part number: 6ES7408-1TA01-0XA0.
- Check rack mounting hardware.
2. Mechanical Inspection
- Inspect fan blades.
- Check bearings for abnormal noise.
- Verify airflow direction.
- Inspect mounting brackets.
3. Electrical Testing
- Apply 24 VDC supply.
- Verify startup current.
- Confirm fan operation.
- Check status indicators.
4. Monitoring Verification
- Test fan monitoring circuit.
- Verify relay indication.
- Confirm fault detection behavior.
5. Final Documentation
- Record serial number.
- Document operating test results.
- Assign inventory condition:
- New Surplus
- Refurbished
- Tested Used
The Veteran’s Tech Trap Guide
⚠️ Trap #1: Installing the Wrong Fan Voltage Version
The S7-400 family includes different fan assemblies.
Verify before replacement:
- 24 VDC version → 6ES7408-1TA01-0XA0
- 120/230 VAC version → different part number
Installing the wrong voltage version can damage the assembly or create cooling failure.
⚠️ Trap #2: Replacing Fans Without Checking Rack Temperature History
A failed fan may be a symptom of cabinet conditions.
PRO TIP: Check:
- Cabinet ambient temperature
- Dust accumulation
- Air inlet filters
- Nearby heat sources
A new fan will not solve excessive cabinet heat loading.
⚠️ Trap #3: Ignoring Fan Monitoring Signals
The fan assembly includes monitoring capability.
After replacement, verify:
- LED status indication
- Relay output operation
- PLC diagnostic response
A fan that spins is not automatically a fully healthy installation.
Dynamic FAQ
Q1. What is the Siemens 6ES7408-1TA01-0XA0 used for?
The Siemens 6ES7408-1TA01-0XA0 is a 24 VDC fan subassembly for SIMATIC S7-400 racks with 18 slots. It provides forced cooling and fan monitoring for the PLC rack.
Q2. Does the 6ES7408-1TA01-0XA0 provide PLC control functions?
No. It is a cooling accessory, not a CPU, communication module, or signal module. Its purpose is thermal management of the S7-400 rack.
Q3. What rack size is compatible with the 6ES7408-1TA01-0XA0?
This fan subassembly is designed for Siemens SIMATIC S7-400 racks with 18 module slots.
Q4. What voltage does the 6ES7408-1TA01-0XA0 require?
The unit operates from a 24 VDC supply, with an allowable range approximately from 19.2 VDC to 30 VDC.
Q5. What should buyers verify before purchasing a New Surplus 6ES7408-1TA01-0XA0?
Recommended checks:
- Exact Siemens order number
- 24 VDC version confirmation
- Rack compatibility
- Fan operating condition
- Monitoring circuit test results
- Warranty coverage
Q6. Is refurbished 6ES7408-1TA01-0XA0 suitable for S7-400 spare inventory?
Yes, if the fan assembly has passed electrical startup testing, airflow verification, and monitoring checks. For legacy S7-400 systems, maintaining a tested spare cooling assembly can prevent temperature-related PLC interruptions.
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