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Sensus - HRI

Sensus - Hri - Product Image
Brand: Sensus
Category: Metering, Radio Tools & Accessories
Compatible Meters:

All Sensus 620 Water Meters

Product Description

HRI (high-resolution interface) is a universal sensor that 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.

HRI is available in two versions

The HRI-A Pulse Unit is a high-resolution pulser that detects the flow direction.

The HRI-B Data Unit is an electronic register with a data interface that 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.

Features and Benefits

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


  • 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.
Sensus 620MC+HRI

Sensus 620 MC + Installed Sensus HRI B4

HRI Interface Principle

Sensus - HRI - Interface

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

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

HRI Pulse Values


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 - Sensus RF Pulse Unit

Technical Specifications

Power supply

3V Lithium battery with an expected lifetime of 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 equals 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)

Sensus - Hri - A3

Balanced Pulse Output at HRI-A4 - Pulse Unit

Sensus - HRIA4 - Pulse Output

Reverse volume pulses are compensated by an 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.

Sensus - HRI - Electrical Connection
Sensus - HRI - A4

Available variants

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

Sensus - HRI - Available variants

² only for HRI prepared C&I meters like MeiTwin Encoder

The HRI-B has the same pickup principle as the HRI-A. However, 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

Sensus - HRI - B

* Active for HRI Data Unit only External power supply of 5 to 24 V DC possible if data line is not used (green)

HRI-B Pulse Output

Two 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 an identical number of forward pulses. See HRI-A.

Sensus - HRI

Product Code Size Description
HRI-1L/P All Sensus HRI Pulse Unit 1L/P for Sensus 620 Series - Model B4
HRI-10L/P All Sensus HRI Pulse Unit 10L/P for Sensus 620 Series - Model B4
HRI-100L/P All Sensus HRI Pulse Unit 100L/P for Sensus 620 Series - Model B4
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