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Brand: Sensus
Sensus 640 Volumetric Water Meter with Electronic Register
Description
The Sensus 640 is a volumetric piston water meter in a brass body with an electronic register and integrated radio function, in DN 15 to DN 40 at 16 bar and up to 50 degC. The piston and measuring chamber design measures the smallest drops of water, and the electronic register adds a nine-digit display, wireless communication and tamper-proof construction for AMR and AMI systems. Two lithium batteries in the register provide a calculated life of 15 years in the radio profiles stated in the data sheet.
Technical specifications
| Parameter | Specification |
|---|---|
| Product | Sensus 640 volumetric (piston) meter, brass body with electronic register |
| Nominal sizes | DN 15, 20, 25, 32, 40; MAP 16 bar; T50 (0.1 to 50 degC) |
| Permanent flow Q3 | 2.5, 4, 6.3, 10, 16 m3/h |
| Ratio Q3/Q1 | R400 (DN 15 to 20), R315 (DN 25 to 40); further ratios down to 40 available |
| Accuracy class | +/-2 percent (Q2 to Q4) up to 30 degC; +/-3 percent above 30 degC; +/-5 percent (Q1 to Q2) |
| Pressure range and loss | 0.3 to 16 bar; pressure loss class dP 0.63 bar |
| Classes | Environmental I; mechanical M2; climatic 5 to 70 degC; electromagnetic E2 |
| Register | Electronic register with 9 digit LCD (6 for m3, 3 for litres), highest resolution 0.05 litre in test mode; hermetically sealed, IP68, glass and copper casing |
| Radio | Integrated radio functionality in various frequencies; wM-Bus T1 and SensusRF |
| Battery | Two lithium batteries in the register; 15 years calculated life with wM-Bus T1 (3600 s interval) or SensusRF (BUP 15 s / LAT 60 s) |
| Starting flow | DN 15: 1 l/h; DN 20: 2 l/h; DN 25 and DN 32: 7 l/h; DN 40: 12 to 15 l/h |
| Type approval | MID 2014/32/EU: Q3 2.5 DE-07-MI001-PTB002; Q3 4 DE-09-MI001-PTB004; Q3 6.3 to 16 DE-15-MI001-PTB019; OIML R49:2013; EN 14154-4:2014; ISO 4064:2017 |
| Drinking water compliance | KTW/DVGW (D), ACS (F), WRAS (UK), Hydrocheck (B), KIWA ATA (NL) |
Performance and dimensions
| DN | 15 | 20 | 25 | 32 | 40 |
|---|---|---|---|---|---|
| Q3 (m3/h) | 2.5 | 4 | 6.3 | 10 | 16 |
| Q4 (m3/h) | 3.125 | 5 | 7.875 | 12.5 | 20 |
| Q1 (l/h) | 6.25 | 10 | 20 | 32 | 51 |
| Q2 (l/h) | 10 | 16 | 32 | 51 | 81 |
| Length L (mm) | 170 | 190 | 260 | 260 | 300 |
| Weight (kg) | 1.0 | 1.6 | 3.7 | 3.8 | 5.0 |
Electronic register and radio
The register is hermetically sealed in a glass and copper casing, giving protection class IP68, and shows nine digits with icons for alarm, low battery, radio active, hydraulic test mode, flow direction and the programmed unit. Radio is integrated in various frequencies, and the data sheet lists wM-Bus T1 and SensusRF profiles for the battery life calculation. Foreign matter is filtered by a tubular strainer on the inlet or a seat strainer, the meter retains its metrological accuracy in difficult conditions according to the sheet, and a MID seal can be supplied with ratios up to R400. The accuracy class is plus or minus 2 percent between Q2 and Q4 up to 30 degC and plus or minus 3 percent above.
Choosing between the 620 and 640
The 640 differs from the dry dial 620 in having an electronic register and radio, so it is the choice when remote reading, alarms and long battery life are required without an add-on sensor. Select the size from Q3 and the connection, noting the tail threads from G3/4B to G2B and the length options, and check that the radio frequency and protocol match the reading system in use. The installation guidelines are in Sensus’s Volumetric Meter Manual, which is a separate document. Confirm the approvals required by the supply authority, since the certificates listed are the European MID and potable water approvals.
How the Sensus 640 works
Water enters the measuring chamber and moves a piston in a circle. Each turn passes a fixed volume of water. A magnet on the piston turns with it, and the electronic register counts the turns. The register shows the volume on its display and sends it by radio to a reader.
Where the Sensus 640 is used
- Homes and apartments
- Small commercial buildings
- Utility networks with remote reading
- Sub-metering of water use
- Industrial sites with small pipes
Selection checklist for the Sensus 640
- Nominal size DN 15 to DN 40
- Permanent flow Q3
- Ratio Q3/Q1
- Radio protocol
- Pipe pressure
- Water temperature
- Installation length
- Reading method
Installation, commissioning and maintenance notes for the Sensus 640
Flush the pipe before fitting the meter. Fit the meter with the flow arrow in the flow direction. Make sure the meter stays full of water. Check the register display and the radio status after fitting. Replace the meter when the register shows a battery alarm.
Requesting a quotation for the Sensus 640
Please send the size, the permanent flow and the radio protocol. Seven Star LLC serves industrial customers in Oman and the GCC and replies with a quotation based on the information provided.
Sensus 640 sizes
The Sensus 640 comes in DN 15, 20, 25, 32 and 40.
Sensus 640 permanent flow
The permanent flow Q3 runs from 2.5 to 16 m3/h.
Sensus 640 pressure
The maximum working pressure is 16 bar.
Sensus 640 temperature
The water temperature class is T50, up to 50 degrees C.
Sensus 640 accuracy
The accuracy is plus or minus 2 percent between Q2 and Q4.
Sensus 640 display
The register has a nine-digit LCD.
Sensus 640 register protection
The sealed register is protected to IP68.
Sensus 640 radio
The radio protocols are wM-Bus T1 and SensusRF.
Sensus 640 battery
Two lithium batteries give a calculated life of 15 years.
Sensus 640 starting flow
The starting flow is 1 l/h for the DN 15 meter.
Sensus 640 dimensions
The length runs from 170 mm for DN 15 to 300 mm for DN 40.
Meter records for the Sensus 640
Record the meter serial number, the location and the first reading.
Choosing the right Sensus 640 size
Choose the size from the permanent flow, not from the pipe diameter alone.
Documents and quotation
The linked file is the four-page Sensus 640 data sheet LD 1680 INT (09.2021 edition). Before ordering confirm the DN, lay length, radio frequency and protocol, ratio and approvals needed. See also related flowmeters. Seven Star LLC, an independent supplier in Muscat, will prepare a quotation from your project requirements.
Datasheets & Documents
- Datasheet Sensus 640 data sheet (LD 1680 INT - 09.2021-0006) Download
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About brand
Sensus is a water and thermal energy metering manufacturer whose Sensus International business is based in Ludwigshafen am Rhein, Germany. Its range runs from static electromagnetic and ultrasonic meters such as iPERL and Cordonel to volumetric, multijet, turbine and compound meters, with SensusRF radio for fixed-network and walk-by or drive-by reading. Seven Star LLC, an independent supplier in Muscat, lists Sensus meters that are backed by the manufacturer data sheets.\n\n
Sensus meter technologies
\n\nSensus International states that it is one of the few global manufacturers offering both leading static metering technologies, electromagnetic and ultrasonic, alongside traditional mechanical meters. Piston meters such as the 620 and 640, the 420 multijet and the DomoJet single jet cover residential and sub-metering duty, while the WP-Dynamic turbine, the WPV-MS compound meter and the MeiStream Plus bulk meter serve larger flows.\n\n
What we need to quote a Sensus meter
\n\nSend the DN, connection or flange drilling, lay length, ratio, temperature class, the approvals your utility requires (MID, OIML R49, ISO 4064 or potable water approvals) and the radio protocol. Note that the North American iPERL+ is documented in US units and standards, separately from the international range.
Related products
Frequently Asked Questions
The 640 has a brass body with a sealed electronic register and integrated radio, while the 620 has a dry dial mechanical register.
A calculated 15 years for the radio profiles stated: wM-Bus T1 at 3600 s or SensusRF.
IP68.
DN 15, 20, 25, 32 and 40, with Q3 from 2.5 to 16 m3/h.
MAP 16 bar, with a temperature range of 0.1 to 50 degC.

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