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Building and Industry


Sensus HRI Sensor

360° Model Details

Product code: HRI

Product description: HRI - B4/8l; D=1

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HRI (high resolution interface) is a universal sensor which is compatible with a wide range of meters, including single-jet, multi-jet and piston meters with dry-dial and semi-dry registers in glass-copper or plastic housing. HRI can be retrofitted on all Sensus meters since 2008 pre-equipped with an HRI modulator.


Features and Benefits

  • Suitable for a wide range of meters
  • Load-free sensor detecting the pointer‘s rotation
  • May be retrofitted to pre-equipped meters
  • Detects flow direction
  • No influence to the meters performance
  • Contact bounce suppression
  • Self-diagnostics
  • Ultra long battery life
  • Hermetically-sealed housing (IP68)
  • Non magnetic principle

HRI is available in two versions:

The HRI-A PulseUnit is a high resolution pulser which detects the flow direction.

The HRI-B DataUnit is an electronic register with a data interface which supports both hard-wired M-Bus systems and battery-driven MiniBus devices such as mobile meter reading systems. The HRI-B can alternatively be used as a pulse type with configurable pulse output.

The HRI is more than an extension of a simple sensor. It has been expanded to provide a reliable data source for remote reading of a conventional meter. It is the interface for all today’s requirements for data interrogation and remote transmission.

Sensus HRI Sensor
Sensus HRI Sensor

Sensus Model 620 C and HRI Sensor

HRI Interface Principle

The HRI pickup system technology enables the load-free sensor detecting of the pointer‘s rotation of pre-equipped meters


  • Route-planned meter reading for billing, for example mobile reading systems.
  • Load profiles via a fixed network using M-Bus or via radio, telephone or GSM Modem.
  • Industrial application e.g. dosing.
  • Remote reading of flow rate and cumulative flow using a frequency converter.
  • Leakage detection when connected to a data logger.
  • Generation and transmission of flow profiles using a data logger and GSM modem. The design of the HRI allows the system to be installed in extreme conditions, such as flooded meter pits.

HRI-A (pulse unit)

  • No influence to the meter performance
  • Can be retrofitted to pre-equipped meters
  • Detects flow direction

HRI-A and HRI-B are using the same proven pick up principle.

HRI-A4 compensates reverse flow pulses with its balanced pulse output.

HRI-A3 is a special version for applications requiring a direction signal like external radio modules.

Technical specifications

Power supply

3V Lithium battery with expected lifetime 12 years.


max.: d x h - 66 mm x 32 mm

Additional height of the meter: 25.5 mm

Weight: 136 g

Casing: ABS

Colour: grey

Cable length

1.5 m - possible cable extension up to max.

30 m. Transient voltage protection is highly recommended for wiring outside buildings.


  • Storage Temperature: -10 °C.....+65 °C
  • Operation Temperature: -10 °C.....+65 °C ¹
  • Hermetically-sealed housing IP 68
  • EMC acc. EEC directive 98/34 equal European standards EN61000-6-1

¹ Usable on hot water meters up to 90 °C water temperature e.g. Sensus 120C meter. A requirement for this application is that the pulser is in free air to ensure adequate cooling.


(only where direction signal is applicable)

Balanced pulses Output at HRI-A4 (pulse unit)

Reverse volume pulses are compensated by identical number of forward pulses before continuing with output pulses.

A remote counter at the HRI-A4 will represent the identical counter reading as at the meter!

Electrical Connection

HRI-A4 provides a solid state switch

Available variants

The HRI-A4 is available with following alternative output pulse weights: D = 1 or 10 or 100

HRI-B (data unit)

HRI-A. But the HRI-B has a serial output and a pulse output which can be used alternatively. Parallel usage of serial output and pulse output is not recommended and can cause problems.

The serial interface can also be used to configure the pulse output.

Technical Data

  • Cable length 1.5 m (5 m optional)
  • Operational cable length: several km with transient
  • voltage protection
  • Temperature range
    - Storage: -20 °C to +65 °C
    - Operation: -10 °C to +65 °C
  • Battery lifetime: typ 12 years

HRI-B Pulse Output

2 pulse outputs (I1, I2) according to ISO / TC 30 / SC 7 / WG 8

  • Switched voltage: max. 24 V
  • Switched current: max. 20 mA
  • Power input: max. 0,48 VA
  • Pulse length: 124 ms pulse width fixed
  • Memory for up to 1,000,000 reverse pulses (B4)

Depending on the application, the HRI-B Pulse Outputs can be offered in three modes: Mode B2, B3 and B4.

Mode B2

Output l1: Forward flow pulses

Output l2: Reverse flow pulses

Mode B3

Output l1: Forward and reverse flow pulses

Output l2: Flow direction (open = forward)

Mode B4 (default mode)

Output l1: Balanced pulses 3

Output l2: Cable cut detection

Output l2 is permanently closed. If the cable is cut, it can be detected as open.

3 Reverse pulses are compensated by identical number of forward pulses. See HRI-A.

Installation tutorial:

How to Install HRI Sensor to Sensus 620 Water Meter - HERE

Wiring instruction:

Wiring example - Sensus 620 + HRI Sensor to Dcell W Data Logger

PDF Datasheets

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Engineering Data*

2D CAD Drawing

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Engineering Data*
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Product code

Sensus HRI Sensor

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