CDU telemetry for liquid cooling loops
A loop's supply-to-return difference is only 5–10 °F. Two unmatched sensors at ±1 °F each put almost 50 % uncertainty on it, so capacity cannot be verified.
Ask for the specification sheet
One matched pair, one part number.
Five parameters, four instrument classes
| Parameter | Instrument | Value |
|---|---|---|
| Temperature | Matched resistance pair, IEC 60751 Class A | −40 to +150 °C |
| Flow | Electromagnetic, or ultrasonic under the floor | DN25 0.5–18 m³/h, ≈36:1 turndown |
| Differential pressure | Transmitter, 100 kPa filter or 400 kPa loop | ±0.075 % FS |
| Liquid level | Optical point switch or hydrostatic analogue | Cable 0–75 °C |
| Leak | Rope channel, 2-wire detects, 4-wire locates | Fluid reaches the sensor |
Pick the flow principle for the fluid
| De-ionised technology cooling | 0.2–20 µS/cm |
|---|---|
| Glycol premix or facility water | 50–300 µS/cm |
| Electromagnetic floor | 5 µS/cm |
| Below the floor | Near zero, no fault |
Straight runs are part of the accuracy budget
Specified runs are 5× DN upstream and 3× DN downstream. Without them error rises about 1.5 % of reading, three times a ±0.5 % of reading claim.
What the gateway has to absorb
- Fluid Flow Rate
- Inlet Fluid Pressure
- Outlet Fluid Pressure
- Differential Pressure
- Fluid Loop High/Low Differential Pressure
Ten-point controller: 5 universal inputs, 2 analog outputs, 3 triac outputs, 1 RS-485, 2 Ethernet, expandable to 50 points.
Two-of-two, so a sensor earns its alarm
| Alarm flooding | Two-of-two logic |
|---|---|
| Too many nuisance alarms | Redundant, cross-checked sensors under a two-of-two rule |
| Operators learn to ignore it | Either the tray sensor or the manifold rope detects, and the channel alarms |
| Condensation reads as a leak | Both detect, and intervention is permitted |
Supply water stays 2 °C (3.6 °F) above dew point.
Where the instrumentation stops
No coolant distribution units, no cold plates.
The loop delivered the flow and ΔT it was designed for.
Rack TCS 10–100 L/min against facility 140 L/min.
A rack CDU secondary holds 5.7 L against 3.4 L primary. Fill and flush runs through fill and flush; commissioning through technical resources.