Which Milesight level sensor do I need? EM400-UDL vs EM500-UDL vs EM410-RDL
Short answer: For vessels up to 5 m or 10 m the ultrasonic EM400-UDL and EM500-UDL share the same probe ranges: the EM400-UDL screws to a flat surface and adds temperature, the EM500-UDL mounts to a pole, wall or DIN rail and buffers readings. Choose the EM410-RDL when the environment defeats ultrasound – it is 60 GHz radar, reaches 12 m and is the only IP68 unit here.
Which Milesight level sensor do I need?
Choose the EM400-UDL if it screws to a flat surface over a tank up to 5 m or 10 m deep in a humid space. It is the only one of the three with a dedicated temperature sensor (-40 to 125°C), it is rated to 95% RH, and its IP67 housing adds an internal damp-proof coating. Its -30 to 70°C window is the wider of the two ultrasonic models.
Choose the EM500-UDL if the mounting point is a pole, wall or DIN rail rather than a flat lid, or if LoRaWAN coverage on site is unreliable. It stores 1,000 readings on board with retransmission and retrieval, so a missed uplink is not a lost reading, and it adds Milesight D2D to trigger another Milesight device directly. Its probe ranges match the EM400-UDL.
Choose the EM410-RDL if you need beyond 10 m, if the sensor will live in a wet or dirty chamber, or if the target is a liquid or smooth-faced solid needing millimetre reads. It measures 0.3 to 12 m, its PVDF body is IP68 (1 m underwater, 48 hours), it runs from -40 to 70°C and it takes a G1½” tank thread. It is the most expensive of the three.
Ultrasonic or radar – when does the EM410-RDL earn the difference?
This is where choices go wrong. The EM410-RDL is not an ultrasonic sensor. It is 60 GHz millimetre-wave radar, rated as unaffected by dust, condensate, temperature and acoustic noise – the same conditions that degrade an ultrasonic echo. Every other Milesight level sensor here measures by bouncing sound. A dusty silo, a steaming chamber or a tank deeper than 10 m points to the EM410-RDL; clean air inside 10 m does not.
Beam width favours radar in a narrow shaft too: the EM410-RDL’s beam is 8°, so it illuminates far less of its surroundings. The datasheets state no beam angle for the EM400-UDL or EM500-UDL, so those two cannot be compared on it.
EM400-UDL or EM500-UDL – what actually separates them?
Not the measurement. Both are non-contact ultrasonic, both take the same four probes (C050 and C100 standard, W050 and W100 pro), both resolve to 1 mm and both are quoted at over ten years at a ten-minute interval. The specs separate them on mounting and data handling only. The EM400-UDL screws to a flat surface, runs two 9000 mAh cells and tolerates more moisture; the EM500-UDL mounts to a pole, wall or DIN rail, runs one 19000 mAh cell, configures over USB-C as well as NFC, buffers readings and is LoRaWAN Certified. Nothing in the data makes one more accurate than the other.
Milesight EM400-UDL Ultrasonic Distance/Level Sensor
EM400-UDL-868M
Price range: £194.52 through £366.60 ex VAT (£233.42 – £439.92 inc. VAT)
Measuring range (probe dependent)C050 25 ~ 500 cm; C100 25 ~ 1000 cm; W050 30 ~ 500 cm; W100 50 ~ 1000 cm
View the EM400-UDL-868M
Milesight EM500-UDL Ultrasonic Distance/Level Sensor
EM500-UDL-868M
Price range: £202.01 through £344.16 ex VAT (£242.41 – £412.99 inc. VAT)
Measuring range (probe dependent)C050 0.25 - 5 m; C100 0.25 - 10 m; W050 0.3 - 5 m; W100 0.5 - 10 m
View the EM500-UDL-868MMilesight EM410-RDL Radar Distance/Level Sensor – EM410-RDL-868M
EM410-RDL-868M
£224.45 ex VAT (£269.34 inc. VAT)
View the EM410-RDL-868MSpecification comparison
| Specification | EM400-UDL-868M | EM500-UDL-868M | EM410-RDL-868M |
|---|---|---|---|
| Approvals | CE, FCC; RoHS | CE, FCC, ISED, Telec, LoRaWAN® Certified; EN 55032/EN 55035; EN 62368-1; RoHS | — |
| Configuration | Mobile app via NFC (card emulation mode supported) | Mobile app via NFC, PC software via USB Type-C, downlink | — |
| Dimensions | 118 × 65 × 80 mm | 156.1 × 71 × 69.5 mm (6.1 × 2.8 × 2.7 in) | — |
| Frequency | CN470/IN865/RU864/EU868/US915/AU915/KR920/AS923-1&2&3&4 | CN470/IN865/RU864/EU868/US915/AU915/KR920/AS923-1&2&3&4 | — |
| Housing & colour | ABS + PC (UL94 V0); black grey (C050/C100), grey (W050/W100) | ABS + PC; black grey (C050/C100), grey (W050/W100) | — |
| Ingress protection | IP67 (plus internal damp-proof coating) | IP67 | — |
| Installation | On flat surfaces with screws | Pole, wall or DIN rail mounting | — |
| LoRaWAN mode | OTAA/ABP Class A | OTAA/ABP Class A | — |
| Measurement principle | Non-contact ultrasonic | Non-contact ultrasonic distance / level | — |
| Operating temperature | -30°C ~ 70°C | W050/W100 -30°C to +65°C; C050/C100 -15°C to +60°C | — |
| Power supply | 2 × 9000 mAh ER26500 Li-SOCl2 batteries (replaceable) | 1 × 19000 mAh ER34615 Li-SOCl2 battery (replaceable) | — |
| Relative humidity | ≤95% (non-condensing) | 0% to 80% (non-condensing) | — |
| Resolution | 1 mm | 1 mm | — |
| Sensitivity | -137 dBm @300bps | -137 dBm @300bps | — |
| Tx power | 16 dBm (868 MHz)/20 dBm (915 MHz)/19 dBm (470 MHz) | 16 dBm (868 MHz)/20 dBm (915 MHz)/19 dBm (470 MHz) | — |
| Weight | C050/C100 252.7 g; W050/W100 246.6 g (batteries included) | C050/C100 362.7 g; W050/W100 370.4 g (with battery and mounting bracket) | — |
| Wireless technology | LoRaWAN® (NB-IoT/Cat.M version also offered) | LoRaWAN®, Milesight D2D | — |
| Accuracy | Standard (C050/C100) ±(1+0.3%*S) cm, S=distance, -15°C ~ 60°C; Pro (W050/W100) ±1% FS, -30°C ~ 65°C | — | — |
| Advanced features | — | Data storage (1,000 entries), data retransmission, data retrievability, threshold alarm, change alarm, Milesight D2D controller | — |
| Antenna | — | Internal antenna | — |
| Battery life | — | 10 years (10 min interval, 25°C) | — |
| Battery life (LoRaWAN) | > 10 years (10 min interval, 25°C) | — | — |
| Device position status | Normal/Tilt (3-axis accelerometer) | — | — |
| Measuring range | C050 25 ~ 500 cm; C100 25 ~ 1000 cm; W050 30 ~ 500 cm; W100 50 ~ 1000 cm | — | — |
| Range & accuracy | — | W050 0.3-5 m ±1% FS; W100 0.5-10 m ±1% FS; C050 0.25-5 m ±(1+0.3%*S) cm; C100 0.25-10 m ±(1+0.3%*S) cm | — |
| Temperature sensor range | -40 ~ 125°C, resolution 0.1°C | — | — |
Specifications taken from the manufacturer datasheets. Rows where the models are identical are dimmed. Prices are ex VAT and read live from the catalogue.
Frequently asked questions
Do these Milesight level sensors work on UK LoRaWAN networks?
Yes. All three list EU868, the band used for LoRaWAN in the UK, and all three run OTAA or ABP in Class A. Transmit power at 868 MHz is 16 dBm on every model and sensitivity is -137 dBm at 300 bps.
Which of these can measure a tank deeper than 10 m?
Only the EM410-RDL. Its 60 GHz radar covers 0.3 m to 12 m. The ultrasonic models top out at 10 m with the C100 or W100 probe.
How close to full can each sensor read?
The EM400-UDL starts at 25 cm (C050 and C100), 30 cm (W050) or 50 cm (W100); the EM500-UDL at 0.25 m, 0.3 m or 0.5 m on the same probe set. The EM410-RDL starts at 0.3 m and has a blind-zone alarm.
Which model suits a wet, dirty or flooded chamber?
The EM410-RDL. It is IP68 rated to 1 m underwater for 48 hours, its housing is PVDF, it is rated 0 to 100% RH non-condensing and it operates from -40 to 70°C. The two ultrasonic models are IP67; of those the EM400-UDL is the more moisture-tolerant, at 95% RH with an internal damp-proof coating.