WIRELESS RESISTIVE LEVEL TRANSMITTERS & SENSORS
Battery-Powered Self-Contained Level Sensing Solutions


SM-RL1 | SM-RL1-T | SM-RL2 | SM-RL2-T
HIGHLIGHTS
- Monitor product, interface & temperature using a single Resistive Level Sensor
- Up to a 10-year battery life
- ± 1/8” accuracy on 1/4“ sensor* (T option)
*API 18.2-compliant - ± 1/4” accuracy on 1/2“ sensor
- Flex (PTFE) or rigid (316 SS) sensor option
- Multiple liquid compatibility
- Sensor only requires a one-time calibration
- Installs in minutes: Quick Connect eliminates sensor wiring error and hassle
- Highly resistant to H2S damage, scaling, and paraffin buildup (Limited lifetime warranty, please contact your OleumTech representative
for details) - Self-contained, rugged design, IP66
- Sensor supports a wide temperature range
- -40 ˚C to 120 ˚C / -40 ˚F to 248 ˚F
- 900/915 MHz range: Up to 1.4 Miles / 2.3 km with Clear Line of Sight
- 2.4 GHz range: Up to 1.9 Miles / 3.1 km with Clear Line of Sight
- 868 MHz range: Up to 1.5 Miles / 2.4 km with Clear Line of Sight
- Secure AES encryption
- Class I, Division 1 (Zone 0), Intrinsically Safe
- US Patent #6,967,589 & #8,763,455 B1


Accurate Level Sensing Solution
OleumTech® designed the OTC Wireless Resistive Level Transmitter to connect and power its flagship line of Resistive Tanks Level Sensors for enabling remote collection of critical tank level data. The self-contained, battery-powered transmitter and sensor combination delivers exceptional performance, reliability, and accuracy, and is made to thrive under extreme outdoor conditions.
All OleumTech Resistive Level Sensors offer industry-leading 3-in-1 monitoring capabilities of product (oil), interface (water), and temperature from a single instrument. Ordering the SM-RL2 and SM-RL2-T transmitter option provides two additional discrete inputs, giving you a total of 5-in-1 monitoring capabilities.
The SM-RL1-T and SM-RL2-T options are compatible with the 1/4” resolution sensors providing API 18.2 compliance for handling custody transfer applications while the SM-RL1 and SM-RL2 work with 1/2” resolution sensors. A single, replaceable battery pack powers both the transmitter and sensor and can last up to 10 years.
Reliable, Scalable, and Safe
The field-proven wireless level transmitter communicates with an assigned wireless gateway within the OTC Wireless Sensor and I/O Network, creating a highly scalable network, accommodating virtually any I/O requirement.
OleumTech wireless level transmitters and sensors 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.
Applications
The Resistive Level Sensors are ideal for use as oil level sensors, water level sensors for storage tanks that contain either or both liquid densities. These level instruments are widely used in oil production tank batteries, condensate tanks, water treatment centers, petrochemical and chemical-making plants, wastewater handling and storage facilities, refineries, and power generating plants.
TECHNICAL SPECIFICATIONS
WIRELESS COMMUNICATIONS | |
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Radio Band | ∙ ISM Band (License-Free) |
900 MHz / 915 MHz | ∙ FHSS, FSK, AES Encryption 256-bit (900 MHz), 128-bit (915 MHz) |
2.4 GHz | ∙ DSSS, AES Encryption 128-bit |
868 MHz | ∙ LBT-AFA, AES Encryption 128-bit |
Bit Rate | ∙ 900/915 MHz: 9600 bps / 115.2 kbps; 2.4 GHz: 250 kbps; 868 MHz: 80 kpbs |
Output Power (Max) | ∙ 900/915 MHz: 10 mW; 2.4 GHz: 63 mW; 868 MHz: 25mW |
Receiving Sensitivity | ∙ 900/915 MHz: -110 dBm @ 9600 bps, -100 dBm @ 115.2 kbps |
∙ 2.4 GHz: -101 dBm @ 250 kbps; 868 MHz: -106 dBm @ 80 kbps | |
RF Range | ∙ 900/915 MHz: Up to 7500 Feet / 1.4 Miles / 2.3 km with Clear Line of Sight |
∙ 2.4 GHz: Up to 1.9 Miles / 3.1 km with Clear Line of Sight | |
∙ 868 MHz: Up to 1.5 Miles / 2.4 km with Clear Line of Sight |
HARDWARE FEATURES | |
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Device Functionality | ∙ OTC Wireless Transmitter with Support for Resistive Level Sensors |
Model Configuration | ∙ SM-RL1: 1/2" Resolution, Product, Interface and Temperature (6-pin Quick Connect) |
∙ SM-RL2: 1/2" Resolution, 2 Discrete Inputs + Product, Interface and Temperature (6-pin Quick Connect) | |
∙ SM-RL1-T: 1/4" Resolution, Product, Interface and Temperature (8-pin Quick Connect) | |
∙ SM-RL2-T: 1/4" Resolution, 2 Discrete Inputs + Product, Interface and Temperature (8-pin Quick Connect) | |
Embedded Controller | ∙ Ultra-Low Power RISC Microcontroller with Internal FLASH (Field Upgradeable) |
Configuration | ∙ Standard RS232 Serial / BreeZ® Software for PC (v5.5 or higher for 1/4" Resolution Models) |
Resolution | ∙ Resolution Depends on Sensor Type: 1/4" (6.4 mm) or 1/2" (12.7 mm) |
Accuracy | ∙ 1/4" Resolution Sensor: ±1/8" (2/16") Accuracy; 1/2" Resolution Sensor: ±1/4" Accuracy |
∙ 6.4 mm Resolution Sensor: ±3.2 mm Accuracy; 12.7 mm Resolution Sensor: ±6.4 mm Accuracy | |
2 Discrete Inputs | ∙ Dry Contact, NPN (Sink), Debounce Filter 20 - 2000 ms (Available on SM-RL2/SM-RL2-T) |
Power Source | ∙ Self-Contained, Internal 3.6 Vdc Lithium Battery |
Internal Battery Life | ∙ Up to 10 Years, Based on User Defined Reporting Intervals |
Device Diagnostics | ∙ Health Tags: Battery Voltage, Received Signal Strength Indication (RSSI), RF Refresh, RF Timeout, Error Codes |
MECHANICAL SPECIFICATIONS | |
Dimensions, SM-RL1/SM-RL1-T | ∙ RL1: 5" (W) x 7.9" (H) x 4.4" (D) / 127 mm (W) x 201 mm (H) x 112 mm (D) |
Dimensions, SM-RL2/SM-RL2-T | ∙ RL2: 5" (W) x 12.9" (H) x 4.4" (D) / 127 mm (W) x 328 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) |
Package Weight | ∙ SM-RL1/SM-RL1-T: ~5.5 lbs / 2.5 kg | SM-RL2/SM-RL2-T: 7 lbs / 3.2 kg |
Connection Fitting | ∙ Quick Connect Adapter to Sensor - No Wiring Required, RL2: 2 3/4" NPT Female Ports (Both Plugged) |
Enclosure Casing Material | ∙ Type 4X Aluminum; IP66 |
CERTIFICATIONS & COMPLIANCE | |
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EMC/EMI | ∙ FCC Part 15 (USA), IC ICES-003 (Canada), ACMA (Australia) |
∙ AS/NZS CISPR 32 (Australia), EN55032 & EN55024 (EU) | |
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 |
SENSOR COMPATIBILITY | |
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1/2" Sensor Kits w/Float(s) | 1/2" TGxxxFxx (Flex) and ZGxxxFxx (Rigid) Works with SM-RL1 and SM-RL2 |
1/4" Sensor Kits w/Float(s) | 1/4" THxxxFxx (Flex) and ZHxxxFxx (Rigid) Works with SM-RL1-T and SM-RL2-T |
GENERAL SPECIFICATIONS | |
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Operating Conditions | ∙ Ambient Temperature (Class I, Division 1 / Zone 0): -40 °C to 70 °C (-40 °F to 158 °F) |
∙ Ambient Temperature (Non-Hazardous Applications): -40 °C to 80 °C (-40 °F to 176 °F) | |
∙ Humidity: 0 to 99 %, Non-Condensing | |
Warranty | ∙ 2-Year Parts and Labor |
Country of Origin | ∙ USA |
SENSOR | RIGID: 316 Stainless Steel "SS" | FLEX: Polytetrafluoroethylene "PTFE" |
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Type | Extremely Reliable and Accurate Resistive Reed Switch Technology | |
Measurement Capabilities (3-in-1) | Product, Interface, and Temperature | |
Lengths Offered in US Units | 2 to 26 ft Length in 1 ft Increments | 8 to 38 ft Length in 1 ft Increments |
Lengths Offered in Metric | 0.61 to 7.9 m in 0.31 m increments | 2.44 to 11.58 m in 0.31 m increments |
Resolution and Accuracy | Option 1: 1/2" (12.7 mm) Resolution with ±1/4" ( ±6.4 mm) Accuracy (6-pin Quick Connect) | |
Option 2: 1/4" (6.4 mm) Resolution with ±1/8" (±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) | 3/4" NPT Male | 1" NPT Male |
Temperature Accuracy | ±1 °C | |
Anchor Weight Diameter | N/A | 2.4" / 60.3 mm |
Height of Anchor Weight | N/A | 8 to 19 ft Sensor: 5" |
20 - 28 ft Sensor: 6.75" / 29 - 38 ft Sensor: 8" | ||
Coiled Diameter | N/A | 20" (50.8 cm) Coiled Diameter |
Minimum Measurement from Bottom (Deadband) | 2" (50.8 mm) from Bottom | From Top of Anchor Weight |
Pressure Rating | Float Dependent | Float Dependent |
Sensor Only without Float(s) | 569 PSI (39 Bar) | 142 PSI (9.8 Bar) |
Sensor w/ 316 SS Float - Small* | 440 PSI (30 Bar) | N/A |
Sensor w/ 316 SS Float - Large | 356 PSI (24.5 Bar) | 142 PSI (9.8 Bar) |
Sensor w/ Polyvinylidene Fluoride (PVDF) Float | 72.5 PSI (5 Bar) | 72.5 PSI (5 Bar) |
Float Options: | ||
*316 Stainless Steel - Small, (Fx0) | Compatible Only with Rigid Sensor Length up to 7 ft | |
Product: 0.64 SG, Interface: 0.96 SG, ID 0.72" (18.3 mm), OD 2.05" (52.1 mm), H 2.71” (68.83 mm) | ||
316 Stainless Steel - Large, (Fx1) | Product: 0.62 SG, Interface: 0.95 SG, ID 1.12" (28.5 +/-0.5 mm), OD 2.83" (72 mm), H 4.65” (118 +/-1 mm) | |
Polyvinylidene Fluoride (PVDF), (Fx3) | Product: 0.64 SG, Interface: 0.96 SG, ID 1.18" (30 +0.3/-0 mm), OD 2.83" (72 +/-0.25 mm), H 1.77” (45 +/-1 mm) | |
Operating Temp. Sensing Area | -40 °C to 120 °C (-40 °F to 248 °F) | |
Certifications | Class I, Division 1, Groups C, D T4; Ex ia IIB T4 Ga; Class I, Zone 0, AEx ia IIB T4 Ga | |
ATEX: Sira 16ATEX2229X; Ex ia IIB T4 Ga | ||
IECEx: SIR 16.0079X; Ex ia IIB T4 Ga | ||
Device Compatibility | OleumTech WT, SM, and H Series Resistive Level Transmitters | |
Power | The Sensor is Powered by the Transmitter | |
Kit Ordering #: 1/2" Resolution with Float(s) | ZGxxxFxx | TGxxxFxx |
Kit Ordering #: 1/4" Resolution with Float(s) | ZHxxxFxx | THxxxFxx |
ORDERING INFORMATION | |
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Transmitters | ∙ 900 MHz: SM5000-RL1 / SM5000-RL1-T / SM5000-RL2 / SM5000-RL2-T |
∙ 915 MHz: SM5010-RL1 / SM5010-RL1-T / SM5010-RL2 / SM5010-RL2-T | |
∙ 2.4 GHz: SM5400-RL1 / SM5400-RL1-T / SM5400-RL2 / SM5400-RL2-T | |
∙ 868 MHz: SM5020-RL1 / SM5020-RL1-T / SM5020-RL2 / SM5020-RL2-T | |
Level Sensor Kits | ∙ 1/2" Resolution Sensor Kits: TGxxxFxx (Flex) and ZGxxxFxx (Rigid) (xxx = Length in Inches, Fxx = Float Configuration) |
∙ 1/4" Resolution Sensor Kits: THxxxFxx (Flex) and ZHxxxFxx (Rigid) (xxx = Length in Inches, Fxx = Float Configuration) | |
Wirelessly Connects To | ∙ OTC Wireless Gateway |
Configuration Cable | ∙ SX1000-CC2, 20-ft All-in-One Configuration Cable |
Replacement Battery | ∙ Use OleumTech SX1000-BP3 Only |
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