Practical example 2:
In our second example we have a telecommunications rack with servers and equipment in use. The additional fan installed in the 19 inch rack must be switched on as soon as the temperature reaches +35 °C.
If the temperature in the rack reaches +45 °C, the fans must be switched on and the alarm siren must be activated for 90 seconds.
At the same time, the administrator must be notified by e‑mail and SMS.
The following points must now be observed:
| Device | Description | |
| Temperature Sensor | The temperature sensor installed in the rack. | |
| Power‑1 Fan | Relay 1 connected to the fan. | |
| Power‑2 Alarm | Relay 2 connected to the siren. | |
| Mail Admin | E‑mail notification, defined by the user. | |
| SMS Admin | SMS notification, defined by the user. |
Set threshold and warning values for the temperature sensor
Edit the threshold values for "Warning Level (High)" and "Alarm Level (High)" for the temperature sensor installed in the rack. Set "Warning Level (High)" to +35°C and "Alarm Level (High)" to +45°C. We will disregard the lower warning and threshold values in our practical example and move the sliders all the way to the left.
Configuration of the siren connected to relay 2
Configure the alarm siren with strobe light connected to relay 2 (Power2). Select a label and set the time at which the alarm is activated under "Pulse duration (sec.)".
Store logical schemes in the monitoring system
Under "Logical Scheme," please define the three logical schemes shown below. After creating the rules, please click the floppy disk icon in the upper right corner to permanently save the settings in the monitoring system.
Logical Scheme 1 automatically switches on the fan connected to Relay 1 (Power-1) at +35°C.
Logical Scheme 2 switches on the siren with flashing light connected to Relay 2 (Power-2) for 90 seconds at +45°C (Alarm Level (High)) and sends the configured email and SMS alerts.
Logical Scheme 3 deactivates Logical Schemes 1 and 2 as soon as the temperature in the rack returns to normal (below Warning Level (High) and Alarm Level (High)). In our practical example, this would be when the rack temperature falls below +35°C.