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Remote Terminal Units  RTUS use serial Ports with

Modbus RTU rs485/232/422 

Raveon Provides MODBUS products enabling you to…

  • Implement a Modbus RTU or serial interface into your devices
  • Connect your industrial network to Modbus RTU via serial devices, Ethernet, or Wireless links
  • Interconnect Modbus RTUs or serial networks or wireless networks with any other fieldbus or industrial Ethernet network

SCADA and Telemetry use radio modems to connect The Master Controller to the Slave Device. Connect an RTU radio to the right Sensors to Monitor in remote zones.

  • The MODBUS Protocol Information website has details and example messages about MODBUS.
  • The myriad of IO features in Raveon’s RTU are show in the website IO interfaces   They are all available.
  • Raveon’s RTU technology has many registers, autonomous features, real time clocks, alerts, data logging, and meshing together.
  • These RTUs are excellent for external sensor monitoring.
  • To process something that involves heat, you put a temperature sensor near it in an RTU.

Integrate Modbus RTU devices to Wireless systems

Raveon’s data radio products are well-suited for Wireless Remote Terminal Units (RTU) in the SCADA and telemetry industry. A wireless Slave Device is a wireless RTU, and it keeps the system efficient and save costs, and make easier to install and update.  A Wireless RTU with built-in Slave features such as Raveon’s RV-M21 Tech Series telemetry modems be a Slave Device in a remote area. VHF and UHF radio frequencies over very long range communication ability, and with the fastest transmit / receive hundreds of thousands of meters and may be polled or report-in every day on a single radio channel.

The M21 and M22  Tech Series data radios Raveon supplies can be Modbus RTUs.
They have General Purpose IOs GPIOs.

Raveon has many RTU version with RS-485 and/or Ethernet interfaces.
They use Modbus protocol with a myriad of IO features and Autonomous features.

Raveon’s RTUs called the Remote Autonomous Zone Nodes (RAZN)  can also wirelessly connect.
Your network can wirelessly connect to the RAZN RTUs over many miles using VHF, or UHF data radios.
License free data radios are also available in Raveon’s RTUs with long-range LoRa technology that works many miles.


Integrate Modbus RTU devices into IP system

The RV-M55-E Ethernet Interface Radio, and all of the RTUs Raveon makes have TCP/IP Ethernet interfaces.  The RTU Slave Device can connect to a Ethernet network, or wirelessly to the Ethernet interface data radio.


RTUs that have autonomous features built into them, do all MODBUS RTU operations, and can do reliable autonomous operations to ensure the system is safe.
Boats, Green Houses, Forests, and many places should be monitored to save them. These RTUs can connect to sensors.
These radios also have accelerometers to monitor angle and vibration to remotely wirelessly monitor sensors, angle, vibration or whatever.

To explain environmental monitoring, application note  AN251_Enviromental_Monitoring (pdf) describes Sensor Environmental Monitoring with a RTU. 

A myriad of IO features are available in Raveon’s RTUs.  They are shown on the  RAZN IO Terminal Versions web page. Many different IO features!

The  differential analog inputs for Volt reading or 4-20mA current reading use ultra high 24bit resolution.  Best in the world.

To control  relays, valves, pumps, lights with AC or DC power the RV-N55-3 PLC has binary inputs and 8 switch voltage (SV) outputs to control 8 things.

Water-Free Modbus RTU Running off Battery!  

Raveon Provides MODBUS products that are Water Proof, called the OGGI.

  • Outside Get General Information (OGGI) product RV-M25.
  • Internal data radio to communicate long-range.
  • Waterproof Enclosure for Outside.
  • Internal Batteries to run the OGGI automatically with no DC input.
  • Long-range batteries inside this OGGI can report every day, and the battery can last of many years.

Raveon’s OGGI product has an Antenna Connector on top of it, and a Myriad of IOs on waterproof connectors on the bottom.

  • The OGGI uses MODBUS protocol to communicate.
  • It is setup to Automatically report IO status at whatever time you want. (Daily, Hourly, or Alerts)
  • The MODBUS Protocol Information website has details and example messages about MODBUS.
  • The Enclosure is waterproof, and the battery inside the OGGI can be Solar Powered.
  • Many General Purpose IO (GPIO) terminal features.
  • The OGGI is very efficient, so if you you use solar charging, it can work FOR-EVER!.
  • There is an Accelerometer inside the enclosure to monitor angle changes and vibration.
  • To process something that involves heat, you connect a temperature sensor to the GPIO interface terminal.
  • You can tie this onto a Tree to monitor a sensor, and send wireless data via UHF, VHF, or 915MHz license Free.

Raveon’s Unique Features for Wireless RTUs

  • Low Cost. Raveon’s Tech Series of wireless data modems are the most economical on the market.
  • Easy to use. Plug-in, Turn-on, and GO. Transmit data in = Receive data out.
  • Remote status monitoring including DC voltage, packet error statistics, modem “up time”, and receiver signal strength.
  • GPIO (General Purpose IO) interface options to have the radio modem be your RTU. It can switch DC power on 1-3 terminals. Or measure sensors.
  • FIO (Flexible IO) interface with pins that can be configured as digital inputs or digital outputs.
  • Remote “PING” From any M7 modem, a user may send a “PING” to any other M7 data radio modem to find out the link signal strength.
    This allows quick diagnostics, easy antenna alignment, and reduced site visits.
  • Wide input voltage with high-efficiency switching voltage regulators. Most all allow input voltage from 9 to 30V DC.
  • Capable of store-and-forward repeating operation. Any M21, M8, M7, M6 radio modem may be configured as a store and forward repeater.
  • Small size. Extruded aluminum enclosure is small, and very rugged.
  • Programmable over-the-air data rates. You can choose how your system will work.
    Set the OTA data slower for extended communication range, or set it fast for lowest latency. Your choice.
  • MODBUS messaging. The GPIO and FIO interface IO pins can controlled with MODBUS RTU messages.
  • The RV-M21, RV-M22, RV-M6, RV-M50, RV-N55 RAZN, area all designed by Raveon and Made in America.

Master Controller Wireless Base Stations

RV-M21 and RV-M22 Tech Series Telemetry modems with Slaves

The Tech Series modems comes with multiple front interface options. User for serial data communications, or wireless SCADA and telemetry Modbus RTU.  They reliably pass messages with these protocols, and if you need to route the data to a variety of various servers and base stations, a smart network gateway can also be used. 

Modbus RTU options with the GPIO and FIO interface. Reliable secure wireless data modems in VHF, UHF, and ISM bands. Send receive raw data, or utilize MODBUS or WMX messaging to control and monitor remote devices.

The Tech Series radio modems are the most flexible RF modem architecture on the planet. They have a myriad of IO options:

  • RS-232   UART Serial. Any baud rate you want to use.
  • RS-422  UART 2-wire Serial. Any baud rate you want to use.
  • RS-485  UART 2 or 4 wire serial. Any baud rate you want to use.
  • USB   to plug into a PC.
  • GPIO   General Purpose IO (Digital IO, Analog input, voltage reading, Switched DC out)
  • Analog   Analog radio for voice communications.
  • FIO   Flexible IO with configurable digital inputs and outputs.
  • CLO is a Current Loop Output CLO that output 4-20mA received from a sensor in a remote area.

For many SCADA systems, the radio modem can be used to communicate with the remote terminal units in very remote areas.  These radio modems are very long range, reliable, and secure.

The RV-M21 are 5watt large radios.  The RV-M22 are miniature low-cost data radios for UHF, VHF, or license free ISM bands.
On the GPIO radio, you can connect SCADA Sensors to Monitor that output 4-20mA. The GPIO will mimic the sensor a long ways away to this modem with Current Loop Output CLO that will output the 4-20mA signal in.

Miniature Long Range Radio Modem Inside your RTUs

Raveon’s M6 and M50 data radio modems are miniature ultra-low-cost radio modem for use in your products.

If you make RTUs, you can put this inside it to communicate wirelessly many miles away.

It is available in various bands:   VHF, UHF, MURS, and 915MHz License Free ISM

It is easy to embed inside your products to communicate for many miles.
The M6 in VHF and UHF bands can communicate for 1-30 miles, depending upon the terrain. The ISM band version RV-M50 utilized LoRa long range RF technology, and can reliably communicate 1-20 miles.

It is low-power and reliable ong-range RF. It also can do AES encryption to make your system safe.

SCADA Software

Raveon has a free open-source software app for testing and working with SCADA, Telemetry, and MODBUS products.  It is called SCADA Comm User (SCU)

This SCU program is designed and built for experimenting and testing MODBUS devices such as Raveon’s Tech Series GPIO and FIO wireless RTUs. If you would like to work with the source code, it is open to Raveon’s SCADA users, so please contact Raveon sales department.

How Do SCADA Systems Work?

Supervisory Control and Data Acquisition (SCADA) is a system to monitor and control remote devices.  SCADA systems are critical as they collect and process real time data.

In today’s world, there are SCADA systems almost everywhere. They includes industrial plants, manufacturing, transportation, oil and gas, power distribution, water control and etc.

The main goal of a SCADA system is to monitor and control equipment in the industrial processes for companies in the public and private sectors.

Remote Autonomous Zone Node (RAZN) that is an: RTU/PLC and many other SCADA features.

Wireless long-range Remote Autonomous Zone Node (RAZN) is for smart SCADA and Telemetry nodes with general purpose control capability in a compact, cost-effective package.
There are many different RAZN version, for many different types of systems. A myriad of IO interfaces are available.
RAZN can switch on/off 8 AC and DC power outputs, and convert up to four analog devices, 8 digital inputs, and 2 switch inputs, into: Ethernet/IP or MODBUS-TCP.
Many analog sensor inputs with ultra-high resolution ADCs to Monitor, control, and record things over many miles.
The RAZN uses MODBUS commands to be an RTU, and do many programmable logic features (PLC) also.
An its huge Autonomous features can Autonomously do what you need to ensure gets done, even if communication fails, so the RAZN can save your system,.. City,.. State!


  • Modbus was developed by Modicon and also today it is managed by Modbus User Organizations. Modbus is application-layer messaging protocol.
    Modbus is an open Master/Slave application protocol, that can be used on several different physical Layers.
  • Modbus provides communication between client/server devices connected to different types of buses or networks.  Modbus-RTU (Remote Terminal Units) means that the Modbus protocol is used on serial lines with an RS-485, RS-232 or similar interfaces.  Many automation systems have Modbus-RTU interfaces for communication. Modbus devices are certified by the Modbus User Organization for interoperability and conformance to the Modbus specification.
  • It uses a simple message structure, making it easy to deploy. It takes just a matter of days to implement, which can save months of work.
  • MODBUS is great, so there is no need to learn and deploy other protocols.  The MODBUS Information website has details and example messages about MODBUS.
  • The Modbus TCP protocol version is similar to the MODBUS RTU version, and the TCP version is optimized for Modbus communication via TCP/IP.
  • The format of the data is flexible. RTU devices store important values of different data types in various 16 bit data registers. A register could contain one analog value, a collection of binary values, or something else.
    A database or a spreadsheet with two columns: one column contains the register name, and the other column contains the register value. That is what holding registers are, and you can configure an RTU to only collect data from the registers you want.
  • RAZN RTU can monitor the Sensors to Monitor  and also control anything.


  • Modbus messages can also be sent over Ethernet using TCP/IP connections to RTUs.  These Modbus messages are packed as a single bit, or 16-bit word packets.
  • The Modbus TCP protocol is similar to the Modbus RTU protocol, and the TCP version is optimized for Modbus communication via TCP/IP.
  • The MODBUS Information website has details and example messages about MODBUS.

RS-485 Computer Interface for RTUs

Raveon can supply an RS-485 interface with USB connection, and they are available online at many sites.

This USB to RS485 interface works great.

Through this USB -to-RS485 cable, you can establish a connection to your RTU with  rs485 device.

USB interface chip is CP2102 from SILICON LABS, and this cable has a TVS diode and a self-recovery fuse.

This is made by DSD TECH.


The 5 Pin RS-485 serial port interrace on the RAZN can be adapted to RS232:

  Many converters are available, and Raveon can supply them if you want them.

The RAZN is wired with 4 wires for communication and a Ground is preferred also.

A+ and B- are the input pins to the RAZN.  Y+ and Z- are the output pins.

Isolated GPIOs and 3-pin Solenoid Drivers


4 Switch Voltage outputs
to drive 3-pin solenoids.

Analog inputs

4-20mA inputs

Digital Input

3 digital IOs.

2-Pin Solenoid Driver. Isolated IOs


Many Isolated IOs:

4 Solenoid Drivers
to control 4
2-pin solenoids.

2: 4-20 or Votltage input.

2 digital inputs

3 additional digital IOs
2 out,  1 in


This RAZN version has:

8 Switched voltage Outputs
AC or DC output.

8 Button Inputs.

Digital inputs to
monitor buttons
or  sensors.

Isolated IOs and 3-pin Solenoid Drivers


8 Flexible IO for GPIO input or output.

2 Ultra High Resolution Analog Inputs
4-20mA, Current, or Voltage.

1 Relay Driver

List of Remote Autonomous Zone Node (RAZN) Versions Created by Raveon.

RTUs with PLC features.

Button Inputs, switched voltage outputs.

Many 2-pin solenoid drivers, and IO features.

RV-N55-7  SCADA and Telemetry GPIOs
Ultra high resolution 4-20mA and voltage sensors and GPIOs.

Solenoid drivers, 4-20mA monitoring, and GPIO features.

Each of these RAZN versions have many similar version with various IO and interface features.
All can communicate with Ethernet, Data Radios, and or RS-485.

The utilize MODBUS RTU and MODBUS TCP communication to work as RTUs.
Each RAZN can Logically Control itself or others over long-range wireless systems.
Raveon’s data radios can be included an a RAZN to work over long range RF systems.  1-50 miles.

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