D3 · Specialist

Coolant flow at the CDU.

Real-time flow monitoring of the coolant in data-centre coolant distribution units (CDUs), built for continuous operation. It has RS485 (Modbus) and 4–20 mA outputs.

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At a glance

What D3 does, in plain words.

What it measures: Liquid flow; How much liquid moves through the pipe.
How it installs: Clamp-on; Sensors fit on the outside of the pipe, so the pipe stays closed.
How it connects: RS485 / 4–20 mA; Wired into control systems over Modbus RS485, or as a 4–20 mA signal.
Pipe sizes: DN20–DN80; DN is the nominal pipe size, roughly the inside diameter in millimetres.

Why D3

D3 in short.

D3 is a CDU coolant monitor for data-centre liquid cooling. It measures coolant flow from outside the pipe, without cutting the pipe or touching the liquid, so there is no leak risk.

It is compact enough for tight spaces and installs in four steps: clean the pipe, fit the clamp, tighten the screws, then set the pipe size and measure.

±2% of reading
Clamp-on for stainless steel pipes DN20–DN80
RS485 Modbus and isolated 4–20 mA
IP65 with an M12 connector cable
Four-step installation

Where it is used

Data-centre CDU cooling
HVAC systems
Water and wastewater management
Process industries
Energy management

D3 front view

How it works

Sound with the flow arrives sooner.

Two sensors on the same side of the pipe take turns sending sound through the water. Sound travelling with the flow arrives slightly sooner than sound travelling against it; the meter turns that time difference into flow, which is why it needs to know your pipe.

How clamp-on ultrasonic measurement works →

Pipe & installation

What the meter needs to know about your pipe.

These are set up on the meter after installation. Pipe size and transducer type are decided when ordering.

Pipe & installation guide pipe materials, sizes, setup checklist

Stainless steel · 2″ example

A smooth metal surface. Clean the spot, add coupling gel, then clamp the sensor on.

60.3mmacross the outside

2.8mmwall thickness

54.8mmacross the inside

Pipe sizes are names, not measurements: a 2″ pipe is 2.375″ across.

The meter needs Pipe size Wall thickness Material: Stainless steel

Technical details standards, OD / ID, both units

Standard: ASME B36.19 · 2″ Sch 10S
Outside diameter (OD): 2.375″ (60.33 mm)
Wall: 0.109″ (2.77 mm)
Inside diameter (ID): 2.157″ (54.79 mm)
Meter parameters: OD · wall · material

This guide shows what a clamp-on meter needs to know about a pipe. It does not mean every model fits every pipe: check the specifications below or ask an engineer.

Specifications

Check the fit before you specify.

The short version is above. These are the specifications published for D3; values that are still being checked are left out.

Performance

Flow velocity: 0.3–5.0 m/s (1.0–16 ft/s)
Accuracy: ±2% of reading (0.3–5 m/s)
Repeatability: 0.4%
Pipe sizes: DN20, DN25, DN32, DN40, DN50, DN65, DN80
Medium: Water, deionized water, ethylene glycol–water mixture, propylene glycol–water mixture, oil-based coolant, fluorocarbon fluid
Coolant concentration: Confirmed with the customer for each project
Application: Data-centre liquid cooling
Pipe material: Stainless steel

Function

Communication: RS485 with Modbus protocol
Output: 4–20 mA, max. load 500 Ω, isolated
Power supply: 10–36 VDC, 500 mA max.
Keypad: 3 touch keys
Display: 1.54-inch colour LCD, 240 × 240
Transmitter temperature: −10 °C to 50 °C
Transducer temperature: 0 °C to 60 °C
Humidity: 20–90% RH, non-condensing
Ingress protection: IP65

Physical

Housing: PC engineering plastic
Pipe clamp: Aluminium alloy
Transmitter: Integrated
Transducer: Clamp-on
Cable: Ø5 six-core cable with M12 A-coded connector, 2 m

Wiring (M12 cable)

Brown (+): Power supply 10–36 VDC
Black (−): Ground
Blue (A): RS485+
White (B): RS485−
Red (I+): 4–20 mA+
Grey (I−): 4–20 mA−

Need a value that is not listed, or the datasheet for your configuration? Ask an engineer.

What these terms mean

DN: Nominal pipe size, roughly the inside diameter in millimetres (DN50 ≈ 50 mm).
Clamp-on: Sensors strap to the outside of the pipe. No cutting, no shutdown for installation.
PoE: Power over Ethernet: one network cable carries power and data.
LoRaWAN: Long-range, low-power wireless. Readings travel through a gateway to a network server.
Modbus RS485: A wired connection widely used by building and industrial control systems.
4–20 mA: An analogue signal where the current represents the reading.