Issue
Can the Power Supply (PS), Automation Server (AS/AS-P), and I/O module backplane assembly be installed vertically instead of horizontally when cabinet space is limited?
Product Line
- EcoStruxure Building Operation
Environment
- Power Supply (PS-24V)
- Automation Server (AS-B, AS-P, AS-P-3)
- Central I/O Modules
- Hardware installation in control cabinets
Cause
Customers may prefer a vertical installation due to cabinet layout constraints or conduit routing.
Resolution
The system is designed, tested, and supported for horizontal mounting only.
Vertical installation is not a supported mounting method because it reduces the effectiveness of the modules' natural convective air cooling. Reduced ventilation can increase the internal operating temperature of the modules, which negatively impacts component lifetime.
Key considerations:
- The system is specified to operate at temperatures up to 50°C (122°F) when mounted horizontally.
- Increased internal temperature can significantly reduce the lifetime of electrical components.
- The Automation Server (AS) is considered particularly sensitive because:
- The CPU generates heat.
- Critical power-retention components used during shutdown and restart are affected by elevated temperatures.
- During normal operation, no immediate symptoms may be visible.
- Long-term exposure to elevated temperatures can result in hardware reliability issues, including failure to restart after a power cycle.
Vertical Installation Considerations
- Ambient temperature should not exceed 35°C (95°F).
- Power supply loading should be reduced from 30 W to 25 W.
- Convective air cooling relies on warm air rising through the module enclosure and being replaced by cooler air from below. Horizontal installation supports this airflow pattern and is therefore preferred.
Risk Mitigation
To minimize risk when cabinet constraints exist:
- Always mount the Power Supply (PS) and Automation Server (AS) horizontally whenever possible.
- I/O modules may be mounted separately and connected using an S-Cable.
- If operating temperatures are near the maximum rated temperature, provide cabinet ventilation or external cooling in addition to mounting the PS and AS horizontally.
I/O Bus Backplane Requirements
- More than one Automation Server cannot be connected to the same backplane because the backplane provides a communication path between connected units and Automation Servers cannot communicate on the backplane.
- The I/O Bus supports 32 slots, including the Power Supply and Automation Server.
- Empty backplane positions still consume a slot.
Additional Information
Important installation requirements include:
- Install the Power Supply, Automation Server, and Central I/O modules horizontally with the device label upright and reading left to right.
- Install devices on a horizontal DIN rail to ensure proper airflow and cooling.
- Vertical installation may exceed thermal specifications and reduce product lifespan.
- The I/O bus supports a maximum of one Automation Server per I/O bus.
- I/O bus device order must be maintained:
- Position 1: Power Supply
- Position 2: Automation Server
- Position 3-32: Central I/O modules and additional power supplies as required
- The I/O bus supports a maximum of 32 positions.
- S-cables may be used to connect multiple DIN rail sections while maintaining I/O bus continuity.
Conclusion: Horizontal mounting is the only supported installation method. If vertical mounting is used, it is not a supported installation method and is performed at the installer's risk. Maintaining operating temperatures well below the maximum rated value is critical to reducing the risk of reduced product life and long-term reliability issues.
