Autonomous Wireless Modbus-LoRaWAN Gateway ROSSMA® IIOT-AMS Modbus Ex

The autonomous ROSSMA IIOT-AMS MODBUS Ex Stand-alone meter-switch is designed for independent polling of industrial sensors and controllers via RS-485 interface (Modbus RTU protocol) with subsequent wireless data transmission over LoRaWAN or NB-IoT networks.

The device operates autonomously from built-in battery and can be used in hazardous areas (explosion protection marking 1Ex e IIC T4 Gb X / 1Ex db IIC T5 Gb X).

Fig. ROSSMA IIOT-AMS MODBUS Ex Stand-alone meter-switch appearance

Compatible Sensors

Pressure Sensors

• Metran-100, 150, 300 (pressure, vacuum, differential pressure)
• Sapphire-22 (gauge pressure, absolute)
• Rosemount 3051 (pressure, flow)
• OVEN PD100 (universal pressure transmitter)
• Endress+Hauser (Cerabar, Deltapilot)
• Other pressure sensors with RS-485 interface and Modbus RTU protocol

Temperature Sensors

• Metran-286 (intelligent temperature sensor)
• OVEN TRM (temperature controllers)
• Termodat (temperature transmitters)
• Yokogawa (thermocouples, RTDs)
• Other sensors with thermocouple or RTD

Level Sensors

• Metran-100-DU (hydrostatic level meter)
• Sapphire-22-DU (level meter)
• OVEN PD100-DU (level sensor)
• Krohne Optiwave (radar level meter)
• Endress+Hauser Micropilot (radar level meter)
• Vega PULS (radar level meter)

Gas Detectors (Gas Analyzers)

• DAH-M (methane detector)
• Senson-SD (gas detector)
• Hobbit-T (methane analyzer)
• ESSA-CO (carbon monoxide analyzer)
• OVEN GPR (gas converter-regulator)
• Other gas analyzers with Modbus RTU

Equipment is registered in the register of the Ministry of Industry and Trade of the Russian Federation as equipment manufactured on the territory of the Russian Federation (Conclusion 48859/11 dated June 11, 2021).

WARNING: The meter-switch is equipped with a built-in non-rechargeable lithium-thionyl chloride (LiSOCl₂) battery ER34615M/T manufactured by FANSO. Attempting to charge the battery may result in fire!

Battery Life Calculator

Technical Specifications

Connection Interfaces

• 1 serial interface: RS-485 (Modbus RTU)
• Discrete inputs: 3 multifunctional inputs (pulse counting or status monitoring)
• Built-in temperature sensor: yes (sent with each transmission)
• Battery voltage measurement: yes (charge monitoring with each transmission)

Power Supply

• Power type: built-in battery (autonomous)
• Voltage: 3.6 V
• Battery type: ER34615M/T (FANSO)
• Chemistry: LiSOCl₂ (lithium-thionyl chloride)
• Capacity: 14,000 mAh (14 A/h) — standard configuration
• Capacity: 28,000 mAh (28 A/h) — compact extended configuration
• Capacity: 126,000 mAh (126 A/h) — extended configuration
• Form factor: D (34.2 mm × 61.5 mm)
• Service life: up to 10 years (at once per day transmission)
• Maximum packets: 40,000 ± 10% (for 14 A/h battery)

Note: Service life depends on sensor polling frequency and data transmission period. For extended life, transmission interval of at least 1 hour is recommended.

Operating Characteristics

• Operating temperature range: -55…+80°C
• Relative humidity: up to 95% at +25°C (non-condensing)
• Atmospheric pressure: 84...106.7 kPa
• Protection degree: IP66 (explosion-proof version)
• Explosion protection marking: 1Ex e IIC T4 Gb X / 1Ex db IIC T5 Gb X
  • X mark means special conditions: operating temperature range -55°C...+80°C

LoRaWAN Characteristics

• Device class: A or C
• Frequency plan: RU868, EU868, IN865, AS923, AU915, KR920, US915, KZ865, custom (based on EU868)
• Activation method: ABP or OTAA (configurable), default ABP
• Transmission interval: configurable via LoRaWAN (from 1 minute)
• Receiver sensitivity: -138 dBm
• Radio range: up to 5 km in urban areas; up to 15 km in rural areas
• Transmitter power: 25 mW (default), maximum 100 mW
• Antenna type: internal

NB-IoT Characteristics

• Frequency bands: B1/2/3/5/8/12/13/17/18/19/20/25/26/28/66/70
• Data rate: 25/20 kbps (single-tone) or 60 kbps (multi-tone) (DL/UL)
• Transmission interval: configurable
• Sensitivity: -138 dBm
• Radio range: up to 5 km in dense urban areas; up to 15 km outside populated areas

Design and Dimensions

• Housing dimensions: 80×75×55 mm (standard), 260×160×90 mm (extended battery)
• Housing material: polycarbonate (UV resistant)
• Cable gland type: M16×1.5 (specified when ordering)
• Mounting: directly to sensor, cable ties to support, DIN rail, wall mount

Capabilities

• Polling up to 8 sensors on one RS-485 bus
• Autonomous operation from built-in battery (up to 10 years)
• Data archiving in built-in non-volatile memory
• Wireless transmission via LoRaWAN/NB-IoT
• Remote configuration via network server
• 3 discrete inputs for pulse outputs or contacts
• Built-in temperature sensor for operating conditions monitoring
• Communication quality control with sensors (Modbus error diagnostics)
• Batch data transmission for energy saving
• Explosion-proof version for hazardous areas

Application Areas

Oil and Gas Industry

• Automated group metering units: pressure, temperature, level control
• Pump stations: pump equipment parameter monitoring
• Tank farms: tank level monitoring
• Compressor stations: gas pressure, vibration, temperature control
• Gas distribution stations (GDS): pressure and gas detection monitoring

Water Supply and Wastewater

• Artesian wells: pressure, water level control
• Clean water reservoirs: level monitoring
• Sewage pumping stations: wastewater level control
• Treatment facilities: treatment process parameter control

Heat Supply

• Boiler houses: coolant pressure, temperature control
• Heat substations: heating parameter monitoring
• Pipelines: pressure and temperature control on network sections

Industrial Facilities

• Production workshops: process parameter control
• Fuel storage: level and gas detection monitoring
• Power facilities: equipment operation control
• Chemical plants: process parameter monitoring

Indication

The ROSSMA IIOT-AMS MODBUS Ex Stand-alone meter-switch has the following indicators:

• ACT — data exchange with sensors via Modbus RTU protocol
• LoRa — data transmission/reception via LoRaWAN network
• NET — NB-IoT network connection
• Success — successful NB-IoT data transmission
• Err — Modbus protocol exchange error indicator
• PWR — device power present (battery operation)

The meter-switch has a RESET button for device restart and forced data transmission.

Sensor Connection

RS-485 Connection Diagram

Bus connection topology:

┌─────────────────────┐
│ ROSSMA MODBUS Ex    │
│ Stand-alone         │
│                     │
│  A+  ───────┬───────── A+ (Pressure sensor: Metran-100, ID=1)
│             │
│  B-  ───────┼────┬──── B- (Pressure sensor)
│             │    │
│  GND ───────┼────┼──── GND (Pressure sensor)
└─────────────┘    │
                   ├──── A+ (Temperature sensor: Metran-286, ID=2)
                   │
                   ├──── B- (Temperature sensor)
                   │
                   ├──── GND (Temperature sensor)
                   │
                   ├──── A+ (Level sensor: OVEN PD100-DU, ID=3)
                   │
                   ├──── B- (Level sensor)
                   │
                   └──── GND (Level sensor)

IMPORTANT: Maximum RS-485 bus length: 1200 meters. Use signal repeaters if exceeded.

Terminal Block Pinout

Firmware

Main Firmware (LR-485x1)

Version: 1.5.5 (09.12.2024) — Download

Firmware for ROSSMA IIOT-AMS MODBUS Ex Stand-alone devices with Modbus RTU sensor polling support.

Firmware with Pulse Input Support (LR-485x1-imp)

Version: 1.5.5 (09.12.2024) — Download

Firmware with additional pulse input support for counting pulses from meters and sensors.

How to update: Use ST-LINK programmer for flashing via SWD interface.

Additional Information

• Device Installation — installation instructions
• Battery Replacement — battery replacement
• Protocols and Commands — control commands and data formats
• ROSSMA Configurator — device configuration
• Troubleshooting — diagnostics and problem solving

Related Pages

Software:

• ROSSMA Configurator — Modbus profile settings for sensors
• ROSSMA NETS Server — telemetry viewing, device management
• Data Decoder — Modbus payload analysis

Technical Documentation:

• Exchange Protocols — MODBUS device packet format
• LoRaWAN Technology — RU864 frequency plan, device classes
• Quick Start — first network connection
• Battery Life Calculator — battery life calculation

Other Devices:

• MODBUS — for industrial controllers (220V power)
• MODBUS Utility — for utility meters
• ANALOG Single Channel — for 4-20 mA sensors
• PULSE — for pulse sensors
• Device Catalog — all ROSSMA IIoT-AMS models