ASHRAE Thermal Guidelines for Data Processing Environments specify environmental conditions at the server inlet, not as a room average. Wall and column mounted sensors are explicitly not considered adequate: inlet temperatures differ by several degrees between racks and between the bottom and the top of a rack.


Target envelope: ASHRAE recommends 18°C to 27°C (64°F to 80°F) at the equipment inlet for classes A1-A4. Alarm thresholds are best set against the allowable class range for your equipment rather than the recommended range.

Mounting Guide   Monitoring Standards

With daisy chained sensors, data center operators monitor their racks at a lower cost of ownership than most wired and wireless alternatives. Using just one base unit and one IP address, up to 40 temperature & humidity sensors are deployed across your cold and hot aisles.


The cylindrical enclosure is designed to hang free from the ceiling on its cable rather than sit on a rack door, so the sensor sees the air in the aisle itself and installation does not depend on the cabinet type.

The DAISY-THUM-C connects to a T-daisy chain connector (included) with its 1.5m (4.92ft) cable. The string is controlled by the DAISY-STARTER, which in turn connects to the base unit.

* requires a minimum of 9V power supply at the sensor to operate. The actual number may vary with distance, cable quality, sensor count and power source.

What you need: a base unit (BASE-XX), one DAISY-STARTER per string, and the DAISY-THUM-C sensors themselves. An optional DAISY-BOOSTER restores the string voltage where it drops below the 9V minimum.

Environmental data is only useful where your operators already look. The base unit publishes every sensor on the string over the open, standard protocols that building management, DCIM and network management platforms already speak — so the DAISY-THUM-C drops into the system you run today rather than adding another silo.

Supported Protocols

• BMS integration: Modbus TCP, BACnet IP and Modbus RTU — the native paths into building management systems and their controllers.
• NMS & DCIM integration: SNMP v1, v2c and v3, including SNMP traps.
• Industrial IoT: MQTT for IIoT platforms.
• Email alerting and optional SMS direct from the base unit.

What That Means In Practice

• No vendor lock-in: open protocols, documented registers and OIDs — your data stays yours.
• No proprietary gateway or middleware between the sensor string and your BMS.
• No cloud dependency: everything runs on your own network, behind your own firewall.
• One integration per aisle: a whole string of up to 40 sensors is exposed through a single IP address.
• Powered by and communicating with the base unit (BASE-XX) over RJ45 — data and power on the same cable.
• Optional Monitoring Software adds central dashboards and trending — optional, never required.

Cooling accounts for roughly 30 to 40% of the energy a data center consumes. Every degree the supply air can be raised cuts chiller load and adds free cooling hours — but only measured inlet data makes that safe to do.

Why Room Averages Cost You Money

• Without inlet data, operators cool to the worst case they cannot see — typically 19°C / 66°F "to be safe" — and pay for it every hour of the year.
• Inlet temperatures differ by several degrees from rack to rack and from floor to ceiling, so a wall thermostat tells you almost nothing about the hottest server.
• A single high reading under the ceiling triggers a false emergency while every inlet is comfortably in spec.

What A Measured Aisle Gives You

• Headroom you can prove: ASHRAE recommends 18°C to 27°C (64°F to 80°F) at the inlet for classes A1-A4. Most halls run far below that because nobody can see the margin.
• Move in steps: raise the set point 1-2°C at a time and watch every inlet on the string before going further.
• Find the real constraint: a string across the aisle identifies the one rack holding the whole hall back, which is usually a containment or blanking panel problem rather than a cooling capacity problem.
• Delta T: compare intake and exhaust readings — a difference above 20°C / 35°F points to recirculation or airflow starvation.
• Alert on the allowable range, not the recommended one, so you get warnings that mean something instead of nuisance alarms.

The string carries both data and power, so the cable run has to be planned as an electrical budget as well as a data one.

Cable

• RJ45 CAT 6/7 recommended.
• Up to 100m (330ft) total, subject to cable quality and interference.
• Each sensor adds a 1.5m (4.92ft) drop cable to its T-daisy chain connector.

Power

• Sensor power usage of 120 mW.
• Minimum 9V must still be present at the last sensor on the string.
• Where the voltage along the string drops below 9V, an optional DAISY-BOOSTER lifts it back to 14V and the chain continues.