Your World Seamlessly Monitored 

Your World Seamlessly Monitored 


Battery-Powered Self-Contained Level Sensing Solution



  • OleumTech® field-proven technology running on the
    global Sigfox Low-Power Wide Area (LPWA) network
  • 3-in-1 level monitoring capabilities:
    Product, interface, and temperature
  • SFX-LR51: 1/4” resolution / ± 1/8“ accuracy
  • SFX-LR53: 1/2” resolution / ± 1/4“ accuracy
  • Flex (PTFE) or rigid (316 SS) sensor option, sold separately
  • Sensor requires a one-time only calibration
  • Highly resistant to H2S damage, scaling, and paraffin buildup
    (Limited lifetime warranty, please contact your OleumTech
    representative for details)
  • Battery life up to 8 years
  • Sensor supports a wide temperature range
    -40 ˚C to 120 ˚C (-40 ˚F to 248 ˚F)
  • A global solution – Zones RCZ1/2/4
  • Remote antenna-ready option available
  • Class I, Division 1 (Zone 0), Intrinsically Safe

Easiest Way to Get Data in the Cloud

The OleumTech® Sigfox Ready SFX-LR51 and SFX-LR53 Wireless Resistive Level Transmitters are designed for deployment anywhere in the world that Sigfox has network coverage. By leveraging the Sigfox Low Power Wide Area (LPWA) network, you can take advantage of the world’s leading Internet of Things (IoT) connectivity service, offering a software-based communications solution where all the network and computing complexity is managed in the Sigfox CLOUD™.

Inherently Secure

The Sigfox Ready Transmitters take advantage of the built-in firewall since they are not directly connected to the internet and do not use Internet Protocol. Layered on top of this secure foundation, OleumTech provisions each device with a unique symmetrical authentication key. Each message sent by the transmitter contains a cryptographic token that is computed based on this authentication key and verified by each Sigfox Base Station.

Designed for Use in Hazardous Locations

The Resistive Level Transmitters are certified for use in Class I, Division 1 (Zone 0) hazardous locations. They are Intrinsically Safe, designed not to cause a spark, and can be serviced without being removed from a process. These devices provide the ability monitor up to three process variables: product, interface, and temperature. The SFX-LR51 provides 1/4” measurement resolution while the SFX-LR53 offers 1/2” resolution.

Extremely Reliable

The Sigfox architecture is based on multiple base stations receiving each broadcasted and repeated message, building redundancy into the solution. Data Integrity, availability, and confidentiality are at the core of the offering.


Sigfox Radio Zones/Regions Supported∙ RCZ1: Europe, Oman, South Africa | Certificate ID: P_009D_53CD_01
∙ RCZ2: USA, Canada, Mexico, Brazil | Certificate ID: P_009D_D78E_01
∙ RCZ4: Australia, New Zealand, Colombia, Peru, Singapore | Certificate ID: P_009D_C7B7_01
Wirelessly Connects To∙ Sigfox Base Stations
Data Reporting Modes∙ Analog Input: On Interval or DIN State Change / Discrete Input: On Interval or DIN State Change
Device Functionality∙ Class I, Division 1 (Zone 0) IoT Wireless Transmitter Supporting OleumTech Resistive Level Sensors
Embedded Controller∙ Ultra-Low Power RISC Microcontroller with Internal FLASH (Field Upgradeable)
Configuration∙ OleumTech Sigfox Configuration Tool via RS232 Serial
Model Configuration∙ SFX-LR51: 1/4" Resolution; Product, Interface and Temperature (8-pin Quick Connect)
∙ SFX-LR53: 1/2" Resolution, Product, Interface and Temperature (6-pin Quick Connect)
Resolution∙ Resolution Depends on Sensor Type: 1/4-inch (6.4 mm) or 1/2-inch (12.7 mm)
Accuracy∙ 1/4" Resolution Sensor: ±1/8" Accuracy; 1/2" Resolution Sensor: ±1/4" Accuracy, Temperature: ± 1 ˚C
∙ 6.4 mm Resolution Sensor: ±3.2 mm Accuracy; 12.7 mm Resolution Sensor: ±6.4 mm Accuracy
Reportable Values∙ Product Level / Interface Level / Temperature Level / Battery Voltage
Device Diagnostics∙ Health Tag: Battery Voltage
Dimensions∙ 5" (W) x 7.9" (H) x 4.4" (D) / 127 mm (W) x 201 mm (H) x 112 mm (D)
Package Dimensions ∙ 10.25" (W) x 14" (H) x 6.5" (D) / 260mm (W) x 356mm (H) x 165mm (D)
Weight∙ Net: 4 lbs / 1.8 kg; Gross: 7 lbs / 3.2 kg
Connection Fittings∙ Quick Connect Adapter to Sensor - No Wiring Required (SFX-LR51: 8-pin / SFX-LR53: 6-pin)
Enclosure Casing Material∙ Aluminum, NEMA 4X, IP66
Mounting Holes∙ (4) M5 Female Threads; Horizontal Spacing: 2.76" (70 mm); Vertical Spacing: 3.70" (94 mm)
Power Source∙ SX1000-BP3, Internal 3.6 Vdc Lithium Battery
Internal Battery Life∙ Up to 8 Years, Based on User Defined Reporting Intervals
SENSORRIGID: 316 Stainless Steel "SS"FLEX: Polytetrafluoroethylene "PTFE"
TypeExtremely Reliable and Accurate Resistive Reed Switch Technology
Measurement Capabilities (3-in-1)Product, Interface, and TemperatureProduct, Interface, and Temperature
Lengths Offered in US Units2 to 26 ft Length in 1 ft Increments8 to 38 ft Length in 1 ft Increments
Lengths Offered in Metric0.61 to 7.93 m in 0.31 m increments2.44 to 11.58 m in 0.31 m increments
Resolution and AccuracyOption 1: 1/2-inch (12.7 mm) Resolution with ±1/4-inch ( ±6.4 mm) Accuracy (6-pin Quick Connect)
Option 2: 1/4-inch (6.4 mm) Resolution with ±1/8-inch (±3.2 mm) Accuracy (8-pin Quick Connect)
Sensor to Interface Mating Connection (No Wiring Solution)316 SS Quick Connect: 6-pin Connection for 1/2" Resolution, 8-pin Connection for 1/4" Resolution
Tank Mating Connection (Adjustable Compression Fitting)2-15 ft: 3/4" NPT Male / 16-26 ft: 1" NPT Male1" NPT Male
Temperature Accuracy±1 °C±1 °C
Sensor Rod/Tubing Diameter0.63" (16 mm): 2-15 ft Sensor0.85" (22 mm)
0.85" (22 mm): 16-26 ft Sensor
Anchor Weight DiameterN/A2.88" / 73 mm
Height of Anchor WeightN/AUp to 26 ft sensor: 4.75" / 121 mm
26 - 38 ft sensor: 8" / 203 mm
Coiled DiameterN/A20" (50.8 cm) Coiled Diameter
Minimum Measurement from Bottom (Deadband)2" (50.8 mm) from BottomFrom Top of Anchor Weight
Sensor Pressure RatingFloat DependentFloat Dependent
316 Stainless Steel - Standard (Included w/Rigid <=15 ft440 PSI / 30 BarN/A
316 Stainless Steel - Large363 PSI / 25 Bar142 PSI / 9.8 Bar
Polypropylene (PP) (Inc. w/Flex and w/Rigid >=16ft72 PSI / 5 Bar72 PSI / 5 Bar
Float Options:
316 Stainless Steel - Standard, 440 PSI/30 BarCompatible Only with Rigid Sensor Length up to 15 ft Prod: 0.64 SG, Intf: 0.96 SG, ID 0.72" (18.3 mm)
OD 2.05" (52.1 mm), Inner Clearance: 0.1" (2.6 mm)
316 Stainless Steel - Large, 363 PSI/25 BarProduct: 0.62 SG, Interface: 0.95 SG, ID 1.1" (27.9 mm), OD 2.76" (70.1 mm), Inner Clearance: 0.5" (12.7 mm)
Polypropylene (PP), 72 PSI/5 BarProduct: 0.64 SG, Interface: 0.96 SG, ID 1.1" (27.9 mm), OD 2.91" (73.9 mm), Inner Clearance: 0.5" (12.7 mm)
Operating Temp. Sensing Area -40 °F to 248 °F (-40 °C to 120 °C)-40 °F to 248 °F (-40 °C to 120 °C)
CertificationsClass I, Division 1, Groups C, D T4; Ex ia IIB T4 Ga; Class I, Zone 0, AEx ia IIB T4 Ga, -40 °C ≤ Tamb ≤ 70 °C
ATEX: Sira 16ATEX2229X; Ex ia IIB T4 Ga, -40 °C ≤ Tamb ≤ 70 °C
IECEx: SIR 16.0079X; Ex ia IIB T4 Ga, -40 °C ≤ Tamb ≤ 70 °C
Power (Wireless)3.6 V Lithium Replaceable Battery Pack, 10-Year Life @ 1 min Read Interval
Wireless CompatibilityOTC - WT / SM Series Resistive Transmitters and Sigfox-enabled Resistive Transmitters
Minimum Sensor Read IntervalDown to 5 Seconds
Model #: 1/2" Resolution with ±1/4-inch Accuracy60-4001-xxx60-4101-xxx
Model #:1/4" Resolution with ±1/8-inch Accuracy60-4101-xxx60-4102-xxx
Kit #: 1/2" Resolution with Float(s)ZG-xxx-FxxTG-xxx-Fxx
Kit #: 1/4" Resolution with Float(s)ZH-xxx-FxxTH-xxx-Fxx
1/2" Sensor Kits w/Float(s)1/2" TG-xxx-Fx-x (Flex) and ZG-xxx-Fx-x (Rigid) Works with LR13, LR13-P, LR53, LR53-P
1/4" Sensor Kits w/Float(s)1/4" TH-xxx-Fx-x (Flex) and ZH-xxx-Fx-x (Rigid) Works with LR11, LR11-P, LR51, LR51-P
Flex Sensor Part #Flex 1/2": 60-4101-xxxx; Flex 1/4": 60-4102-xxxx
Rigid Sensor Part #Rigid 1/2": 60-4001-xxxx; Rigid 1/4": 60-4002-xxxx
EMC/EMI∙ FCC Part 15 (USA), IC ICES-003 (Canada), ACMA (Australia)
Safety∙ Class I, Division 1, Groups A, B, C, D T3C; Ex ia IIC T3
∙ Class I, Zone 0; AEx ia IIC T3
∙ ATEX: Sira 13ATEX2142X; Ex ia IIC T3 Ga; II 1 G
∙ IECEx: SIR 13.0054X; Ex ia IIC T3 Ga
Operating Conditions∙ Ambient Temperature (Class I, Division 1 / Zone 0): -40 °C to 70 °C (-40 °F to 158 °F)
∙ Ambient Temperature (ATEX/IECEx): -30 °C to 70 °C (-22 °F to 158 °F)
∙ Humidity: 0 to 99 %, Non-Condensing
Warranty∙ 2-Year Parts and Labor
Country of Origin∙ USA
Model Number(s)∙ RCZ1: SFX-RCZ1-LR51 (1/4" Resolution / 8-pin) | SFX-RCZ1-LR53 (1/2" Resolution / 6-pin)
∙ RCZ2: SFX-RCZ2-LR51 (1/4" Resolution / 8-pin) | SFX-RCZ2-LR53 (1/2" Resolution / 6-pin)
∙ RCZ4: SFX-RCZ4-LR51 (1/4" Resolution / 8-pin) | SFX-RCZ3-LR53 (1/2" Resolution / 6-pin)
Model Number(s) for Remote Antenna-Ready Option∙ RCZ1: SFX-RCZ1-LR51-P (1/4" Resolution / 8-pin) | SFX-RCZ1-LR53-P (1/2" Resolution / 6-pin)
∙ RCZ2: SFX-RCZ2-LR51-P (1/4" Resolution / 8-pin) | SFX-RCZ2-LR53-P (1/2" Resolution / 6-pin)
∙ RCZ4: SFX-RCZ4-LR51-P (1/4" Resolution / 8-pin) | SFX-RCZ4-LR53-P (1/2" Resolution / 6-pin)
Battery Model Number∙ Use Only SX1000-BP3, 3.6 V Lithium Battery Pack
Configuration Cable∙ SX1000-CC2, 20-ft All-in-One Configuration Cable





  • OleumTech field-proven technology running on the global Sigfox Low-Power Wide Area (LPWA) network
  • 3-in-1 level monitoring capabilities: product , interface, and temperature
  • SFX-LR51: 1/4” resolution API 18.2 compliant ± 1/8“ accuracy
  • SFX-LR53: 1/2” resolution
  • Flex (PTFE) or rigid (316 SS) sensor option
    Sensor sold separately
  • “Set it and forget it” one-time calibration
  • Powered by a replaceable internal battery pack
  • Battery life up to 8 years
  • NEMA 4X / IP66 / -40 °C to 70 °C
  • Industrially-hardened self-contained design
  • Remote antenna-ready option available
  • Intrinsically Safe, Class 1, Division 1 (Zone 0) certified