Integration of HW group Perseus Monitoring with Data Center Air Conditioning - Temperature and humidity monitoring & control

pavelacovy
Sep 9
2 min read

The HW group Perseus Monitoring device is designed not only to collect data from air conditioning systems but also to react automatically based on defined rules. The level of integration depends on the interfaces supported by the air conditioning unit.

1. Digital contacts (dry contact)

Most CRAC units provide alarm outputs (fault, normal operation, high temperature).
These can be connected directly to the digital inputs of the Perseus.
Perseus can then:
- log the event,
- send SNMP traps, e-mails, or SMS alerts,
- activate a relay output to control the air conditioning input (e.g., Remote On/Off, Alarm Reset).

2. Analog signals (0–10 V or 4–20 mA)

Some units provide analog outputs (temperature, humidity, cooling capacity).
Perseus can measure these values and use them for alarms or automated rules.

3. Modbus/RTU or Modbus/TCP

Many modern CRAC systems support Modbus communication.
Perseus can read registers (temperature, humidity, modes, energy consumption) and, where supported, write values (setpoints, enable/disable).
Integration requires the Modbus register map from the air conditioning manufacturer.

4. SNMP / BACnet / other communication cards

If the air conditioning unit has an optional communication card (SNMP, BACnet, etc.), Perseus can integrate directly.
Depending on the implementation, Perseus may be able to both read values and send commands.

5. Reactions and automation (Rules)

Perseus supports IF–THEN logic, allowing fully automated responses:

If temperature in the cold aisle > 28 °C → activate relay → start backup CRAC unit.
If air conditioning reports a fault → send SNMP trap + SMS notification.
If humidity drops below threshold → send Modbus command to adjust humidification.

Summary

Monitoring: always possible (dry contacts, analog signals, Modbus, SNMP).
Control: possible when the air conditioning system provides control inputs (On/Off, Reset, Changeover) or supports writable Modbus/SNMP registers.
Advantage of Perseus: centralized monitoring combined with automated response, without the need for manual operator intervention.