# Intelligent Monitoring of Data Center Physical Infrastructure
## 3 Results  
### Monitoring of Data Center Physical Infrastructure  
Figure 1 shows the typical data center technical infrastructure with diesel generators, power supplies, redundant power supplies, UPSs, a cooling system, an air-conditioned system, and technical safety. The status of individual devices in the data center technical infrastructure is obtained via various interfaces and sensors. Data are captured using a programmable logic controller (PLC) through various data capture interfaces (such as Ethernet, Wi-Fi, analog and digital interfaces) and stored in a database. In Figure 1, CeA and CeB represent air conditioners. The purpose of the thermal management is to keep the temperatures in all room spaces below the upper limits required in the standard with the lowest energy consumption [27]. The temperature for the A1 class should be in the range of 15-32 \({}^{\circ}\)C and the relative humidity should be between 20% and 80%, as shown in Table 1[28]. To accurately measure the moisture and temperature in the data center technical infrastructure rooms, industrial humidity probes and sensors are used. SswA and SswB are static transfer switches that have the task of transferring the power from UPS A to (UPS B) in the event of failure of the UPS A. CdevA and CdevB are cooling devices in which the chilled water temperature is allowed in range of 7.3-25.6 \({}^{\circ}\)C in accordance with the maximum allowed IT inlet air temperature, which was, in addition, used to calculate the chilled water temperature. PecdA and PecdB represent cooling device power supplies, and PswCB is an interface for capturing the state of IT equipment power switches and circuit breakers. Experimental equipment (Tier IV):  
- 6 EMERSON chillers (300 KW of cooling capacity each)--periodic autorotation of active versus
- standby (\(N+2\) redundancy), integrated free cooling;  
- 2 EuroDiesel rotary diesel UPSs (1340 KW) (3-5 days autonomy);  
- 1 standard diesel generator (1250 KVA) which can be used for emergency power or non-IT  
- equipment (e.g., chillers);  
- 3 transformers (1 reserve), 2.5 MW (2 separated 400 A); \begin{table}
\begin{tabular}{l l l l} \hline \hline
**Class** & **Dry-Bulb Temperature** & **Humidity Range** & **Maximum Dew Point** \\ \hline
**Class A1 and A4** & Recommended 18 to 27 \({}^{\circ}\)C & 5.5 \({}^{\circ}\)C dew point (DP) to 60\% relative humidity & - \\  & & (RH) and 15 \({}^{\circ}\)C DP & \\ \hline
**Class A1** & Allowable 15 to 32 \({}^{\circ}\)C & 20\% to 80\% & 17 \({}^{\circ}\)C \\ \hline
**Class A2** & Allowable 10 to 35 \({}^{\circ}\)C & 20\% to 80\% & 21 \({}^{\circ}\)C \\ \hline
**Class A3** & Allowable 5 to 40 \({}^{\circ}\)C & 8\% to 85\% & 24 \({}^{\circ}\)C \\ \hline
**Class A4** & Allowable 5 to 45 \({}^{\circ}\)C & 8\% to 90\% & 24 \({}^{\circ}\)C \\ \hline \hline \end{tabular}
\end{table} 
Table 1: American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) thermal guidelines for data centers [29; 30; 31]. Figure 1: Data center technical infrastructure monitoring. * 3 static transfer switches;
* 5 power switches and circuit breakers. * Room 1:
* 44 racks (10 KW each);
* 12 \"Schneider APC StruxureWare \" InRow redundant powers (RPs) (IRP), precision cooling with two-way valves;
* 3 fans and humidity controls of 50 kW cooling capacity each;
* 4 redundant power distribution lines of 400 A. * Room 2:
* 76 racks (20 KW each);
* 32 APC InRow RPs (IRP), precision cooling with two-way valves;
* 3 fans and humidity controls of 50 kW cooling capacity each;
* 16 redundant power distribution lines of 400 A;
* 300 different electric IT devices. Altogether, there were 510 elements of infrastructure used. Table 2 displays the range limits and their monitoring, as well as the on/off states of individual devices. In particular, the temperature ranges that need to be within the specified limits are of special importance. The starting point for monitoring a physical infrastructure is to build a common block diagram for all layers of the data center infrastructure.