SfAR Modbus I/O Modules

Nowadays processes and control systems are characterized by continuously increased complexity and accuracy. Data transmission over a large area within many different sites become more and more challenging. In these cases the I/O modules becomes helpful.

I/O modules simply collect signals from and send signals to devices while communicating with the controller. The inputs are responsible for receiving signals from devices, like switches or sensors, and transfer the data received to controller or any supervisor connected to the module. The outputs, in turn, are responsible for sending signals to devices like relays, other controllers or inverters.

Many types of inputs and outputs in countless combinations are available at the moment to choose from, but there is one solution standing out with its simplicity and multifunctionality – SfAR I/O Modules.

The SfAR standing for Solutions for Automation and Robotics are Modbus I/O modules focusing on bringing functional, simple and cost-effective solutions to the entire cross-section of automation world. The SfAR solution offers its own standard in inputs and outputs, dedicated housings and many useful features making them valuable position on I/O modules market.

Benefits of SfAR I/O Modules

The basic benefit of using I/O modules is that they allow to collect signals using just short cable runs, what reduces costs and eliminates errors and noises related to the cable length. The communication of an I/O module with external controller is done using just a few wires. Instead of routing all the signals to a DDC controller, what most of the times is impossible due to too big distances between signal sources and controllers, or placing another controller near the signal sources, the data is transferred to the I/O modules with short cable runs and sent to the controller using the communication bus.

The system with I/O modules becomes a centralized and distributed system with open-architecture. The I/O module in such system stand for a mediator that unifies all networks and controllers, giving the system many expansion possibilities.

The main idea behind the SfAR I/O Modules is being simple, cost-effective and reliable, while being universal and versatile.

The key benefits of SfAR I/O Modules are:

  • Wide range of Inputs and Outputs

SfAR I/O Modules enable gathering and sending a wide range of signals used in the automation world.

  • Wide range of module types brought in two lines: S-line and 1M-line

Our modules offer various input and output types in the most wanted configurations. The 2 lines, in which SfAR I/O Modules are divided, are the S-line – designed with a small width and wide amount of Inputs and Outputs , and the 1M-line designed for distributed systems, enabling measurement of small amount of signals in a very compact module size.

  • Easy installation and configuration

Every module is easily configurable thanks to the mini-USB port with and the dedicated software – SfAR Configurator, and features making the implementation of SfAR I/O Modules less time-consuming like the DIP switches, for setting the device Modbus address, and Quick Connector – ribbon tape for grouping SfAR I/O Modules and providing them power and communication.

  • Open protocols

Every SfAR I/O Module have Modbus RTU/ASCII on-board supporting up to 128 modules on RS485 bus. There is also a possibility to integrate them into a Modbus TCP/IP network thanks to the dedicated SfAR-S-ETH, a gateway module enabling integration of Modbus RTU network into a Modbus TCP/IP network. Users can change the parameters of the protocols in a matter of seconds using the DIP switches or the software tool – SfAR Configurator.

  • Reliable operation

Inputs and outputs in SfAR I/O Modules is isolated from the power supply and RS485 port using opto-isolators to avoid interferences in signal loops.

  • Standalone control

SfAR I/O Modules, depending on module type, offer various built-in algorithms like counters, timers, alarms, and setting an output depending on the input value. Those features make them applicable as standalone controllers for simple applications. Additionally, the modules support connecting encoders to the digital inputs.

  • Multifunctionality

The SfAR I/O Modules, thanks to wide range of I/O and their unique features, fit almost every purpose. They are great for any type of automation.

The SfAR comes in 2 versions of I/O modules – the S line and the 1M line, both offering their own, unique advantages and making the SfAR brand a complete solution for automation robotics.

The S-line consists of slim modules offering 6-16 inputs and outputs in 12 combinations. Thanks to their size you can fit many of these in the control cabinet. Each module has an opto-isolation between I/Os, power supply and RS485 on-board is a perfect match for a PLC controller as an extension. The S-line as well as traditional modules, offers a module with a Modbus Gateway TCP/IP to Modbus RTU/ASCII – SfAR-S-ETH, which also offers Device Table mode – a mode increasing Modbus RTU-TCP/IP conversion speed much.

The Device Table mode makes the SfAR-S-ETH module send queries, preconfigured on the module’s webserver, to the slave devices and the responses are then saved on the module itself. The DDC controller needs to query the module’s internal Device Table registers to get the data from slave devices without need for the query to go long way to the slaves.

The modules in the S-line consist of:

  • SfAR-S-6RO – a module with 6 relay outputs
  • SfAR-S-6TI – a module with 6 temperature inputs and 2 digital outputs
  • SfAR-S-8AI2DO – a module with 8 analog inputs and 2 digital outputs
  • SfAR-S-8AO – a module with 8 analog outputs
  • SfAR-S-8DI8DO – a module with 8 digital inputs and 8 digital outputs
  • SfAR-S-8DI8RO – a module with 8 digital inputs and 8 relay outputs
  • SfAR-S-8TO – a module with 8 triac outputs
  • SfAR-S-16DI – a module with 16 digital inputs
  • SfAR-S-16DI-M – a module with 16 digital inputs with a FRAM non-volatile memory onboard
  • SfAR-S-16DO – a module with 16 digital outputs
  • SfAR-S-16RO – a module with 16 relay outputs
  • SfAR-S-ETH – a module with 4 digital inputs and 3 relay outputs and with a Modbus RTU-TCP/IP gateway function

The 1M-line consists of small modules with a small amount of I/Os – 7 types of modules with 2 to 4 I/O. Every module with an opto-isolation between I/O, power supply and RS485 onboard is a perfect choice for distributed systems with devices scattered over a large area. Each module in this line was created for specific purpose with main goal – to implement devices without Modbus onboard into Modbus network.

The modules in the 1M-line, with examples of usage, are:

  • SfAR-1M-1AI1DO – controlling lighting in accordance with lightening measurement
  • SfAR-1M-1TI1DO – controlling heater in accordance with room temperature measurement
  • SfAR-1M-2DI1AO – connecting inverter without Modbus onboard into Modbus network
  • SfAR-1M-2DI2DO – connecting valves without Modbus onboard into Modbus network
  • SfAR-1M-4DI – counting signals from encoders scattered over vast production lines
  • SfAR-1M-4DI-M – counting pulses from flowmeters
  • SfAR-1M-4DO – sending multiple start/stop signals in water pump station

SfAR S-line I/O Modules can be configured by DIP Switches and its dedicated software – the SfAR Configurator. Address of the device can be simply set-up from the DIP switch or from the software, where every other parameter or function can be configured and set. The software detects connected SfAR modules automatically and it is possible to preconfigure modules, using just the USB cable, which powers the module, and a PC with SfAR Configurator, before installing the modules on site.

SfAR I/O – Open protocol I/O Modules

By the 2021, the manufacturers of I/O modules try to outdo one another with features offered by their modules, improving communication speed with their modules, making modules more universal or for more specific applications.

The market of I/O modules is forecasted to focus more on smart data, cloud connectivity, IOT and wireless solutions, while not losing its position in retrofitting applications.

The SfAR I/O Modules, despite the advancing technology, will surely find appliance anywhere, thanks to implementation of open protocol and dedicated Modbus TCP/IP gateway. Using open protocol gives the SfAR multiple advantages over new and expensive technologies:

  • Cost-effectiveness – many savings can be made on construction and maintenance, while using open protocols
  • Easy maintenance – Modbus network relies on its simplicity and easy troubleshooting, made with CRC error codes
  • Widely used – in the automation world, the Modbus protocol is common, what makes SfAR I/O Modules a great choice for almost any application
  • Supported by many manufacturers – you can easily implement SfAR I/O Modules into any automation installation using Modbus

What makes SfAR I/O Modules even more special is their possibility to implement them into higher layers of control system like PLC or SCADA, thanks to the dedicated gateway module – SfAR-S-ETH offering communication over ethernet using Modbus TCP/IP protocol.

Inputs and Outputs in SfAR I/O Modules

Application examples

1. Room Zone Comfort
  • 8AI2DO – collecting data from temperature and sensors, sending alarm signals to indicate alarm states
  • 16DI – collecting signals from window open/close sensors

The SfAR I/O Modules can collect all the data required for controlling a room zone comfort as an expansion of a DDC controller by Modbus. Opening a window causes the heating  and lights up an indicator signalizing that the window is open. The temperature and  measurements are sent to a DDC controller, along with a setpoint value from a wall panel, which controls a room zone comfort.

2. Screw conveyors application in wastewater treatment plant

The supervisor gathers information from SfAR modules using Modbus TCP/IP and SfAR-S-ETH as a Modbus TCP/IP to RS485 Gateway.

The SfAR-S-ETH is connected via the Quick Connector to SfAR-S-8AO and SfAR-S-8AI2DO.

SfAR-S-8AI2DO is connected using RS485 to 2 SfAR-1M-2DI1AO modules which then can be connected to next 2 SfAR-1M-2DI1AO and so on.

  • SfAR-S-ETH – operation status, switching auto/manual
  • SfAR-S-8AO – controlling the conveyors performance
  • SfAR-S-8AI2DO – feedback from devices and alarm confirmation
  • 2x SfAR-1M-2DI1AO – controlling the valves and collecting data from flow sensors


People need comprehensive, long-lasting solutions that can be applied to a variety of applications – SfAR solution matches these features perfectly. Offering wide range of modules in many combinations and with many functional features, while being simple to use, is what makes SfAR I/O Modules perfect choice when looking for Modbus modules.