(Client name and specific stations have been withheld.)
Background
Qingdao Metro Line 6 is a key rail link serving the West Coast New Area, and its Building Automation System (BAS) places strict demands on PLC reliability, stability and domestic content. The original system used imported PLC modules, which brought long spare-part lead times, high maintenance cost and slow technical support. Qingdao Xiaoyang Electric took on the packaged upgrade of PLC module boxes at several stations on the line, replacing the core controllers with domestic units.
Customer challenges
- Spare-part supply: imported modules were discontinued or quoted at 6-8 months lead time, disrupting maintenance
- Maintenance cost: high unit price plus chargeable OEM support
- Domestic content: metro projects are progressively localising core equipment, and imported PLCs no longer fit that policy direction
- Compatibility: the new PLC had to interface seamlessly with the existing BAS platform, sensors and actuators
- Schedule: metro operating windows are short, so box replacement had to be completed during night possessions
Our solution
We used the ATEKON NA2000 series PLC as the core controller and delivered a single-source package covering design, cabinet manufacture, program development and on-site commissioning:
- Controller: ATEKON NA2000, CPU CMM2001-D118, Ethernet capable, 100% domestic content
- Power: Mean Well NDR-120-24 industrial supply
- Network: industrial Ethernet switch with ring redundancy so communications do not drop
- Distribution and protection: Schneider breakers with graded protection
- Signal isolation: interposing relay modules protect the PLC and extend service life
- Wiring: disciplined routing, clear wire numbers, labelled terminals for maintainability
Core bill of materials
| No. | Item | Brand and model | Qty |
|---|---|---|---|
| 1 | PLC CPU module | ATEKON NA2000 CMM2001-D118 | 1 |
| 2 | Digital input module | ATEKON DI | 4 |
| 3 | Digital output module | ATEKON DO | 2 |
| 4 | Power supply | Mean Well NDR-120-24 | 1 |
| 5 | Industrial Ethernet switch | Industrial, 8 ports | 1 |
| 6 | Miniature circuit breaker | Schneider iC65N | 3 |
| 7 | Relay module | Shenle, 8 channels | 2 |
| 8 | Terminal blocks | Weidmüller / Dinkle | Various |
Results
- Domestic replacement: 100% domestic core PLC, with ATEKON performance stable and fully meeting metro BAS requirements
- Schedule: all module boxes pre-built in the factory, leaving only wiring and commissioning on site; a single station swap completed within 4 hours
- Cost: around 40% lower than the imported option, with markedly lower lifecycle maintenance cost
- Integration: full compatibility with the existing BAS platform, no changes to supervisory software
- Quality: 72-hour energised burn-in before dispatch, first-time commissioning pass on site, zero failures in service
Customer comment
“Xiaoyang’s packaged service was professional and efficient, and the ATEKON PLC performed beyond expectations on a metro project. The domestic replacement approach is mature and reliable, and we will continue the partnership on later lines.” — Technical lead, project integrator
About ATEKON
ATEKON Technology (Jiangsu) Co., Ltd. is a leading domestic supplier of industrial automation products. Its NA2000 series is widely used in rail transit, power, water and municipal applications and is one of the representative domestic PLC brands. As an ATEKON partner, Qingdao Xiaoyang Electric has extensive experience in packaged domestic PLC systems.