Issue
Can the backplane, which consists of the Power Supply, Automation Server, and I/O Modules be installed in the cabinet horizontally or vertically?
Product Line
EcoStruxure Building Operation
Environment
StruxureWare Building Operation hardware installation in a cabinet with limited space.
Cause
Customer would prefer vertical installation rather than the typical horizontal installation.
More than one Automation Server per Power Supply**
Resolution
What could happen if you mount the system vertically?
Due to the lack of ventilation the temperature will increase, which will have negative impact on component life time.
The operational temperature is defined up to +50°C. At this temperature, the horizontally mounted system will fulfill the specified lifetime of the different electrical components. In a vertically mounted system the temperature will be higher inside the modules, having negative impact on the component lifetime. Unfortunately it is not a linear relationship between temperature and lifetime - the lifetime decreases rapidly with increased temperature.
Not all modules are generating the same amount of heat, and are therefore more or less sensitive to mounting direction. In my view, the most critical component is the AS. The CPU generates heat (even more important on the coming AS-P). In the AS there are also critical components that maintains power during shut-down. These component's life time is effected if the temperature becomes too hot. These components are, as stated, critical during power-down.
How will this be visible to the user? During normal operation, there will be no visible effect. However, after some years when the AS goes through a power cycle, it will not restart.
So, what to do if you have a cabinet with the conduits running vertically?
The official answer is that the system shall be mounted horizontally. This is how the system is designed and tested.
What can you do to minimize the risk you choose to take if not mounting the system horizontally?
The key is operational temperature. If you are far from 50°C, then the risk is less. One thing you always should consider is to mount the PS+AS in the bottom of the cabinet horizontally, and then have the CIO modules vertically, connected via an S-Cable. This is even more important on AS-P. If you are close to 50°C operational temperature, you need to consider external cooling or at least ventilation in the cabinet in addition to mount the PS+AS horizontally.**
To conclude - the system is designed for horizontal mounting and this is the only supported mounting. If you choose to mount it vertically it is at your own risk. Operational temperature is key - you need to make sure it is far from max to decrease risk. Always try to mount the PS+AS horizontally. Negative effect of not managing operational temperature is not visible short term, but can and will effect the life time of the product.
**Ambient temperatures for operating should be taken into consideration. For vertical installations, ambient temperature should not exceed 35 C (95 F) and the load on the power supply should be reduced from 30 watts to 25 watts. Convective Air Cooling is used in the modules anticipating the currents of warm air being allowed to escape the confines of the module casing to be replaced by cooler air from the bottom. Since warm air normally rises, this method usually requires venting at the top and bottom of the casing to be effective. This is why horizontal installations are preferred.
**One PS can supply one or more units connected to the backplane, consisting of several terminal bases connected together. At the moment you cannot connect more than one AS to the backplane though, because the backplane provides a path for communication between the connected units, and two AS cannot communicate on the backplane. StruxureWare Building Operation allocates 32 slots for the I/O Bus including the Power Supply and Automation Server. All devices can be installed on one linear section of DIN rail or they can be installed on multiple parallel sections of DIN rail by using connector cables*. Be reminded an empty position (back plane without module) will still keep a position (slot). As a general rule, there are 10 I/O modules followed by a Power Supply, then 10 I/O modules followed by a Power Supply and 8 remaining slots for I/O modules.Please keep in mind the I/O Bus backplane requires a particular order. Position 1 is always the Power Supply, Position 2 is always for the Automation Server, and then up to 30 remaining I/O devices interlaced with additional Power Supply modules.
