PC Based Distributed IO

Distributed IO (or Remote IO) is used if the point to be controlled and listened is far away from the computer system and high communication speed is not necessary.

IO devices such as digital IO, analog IO, counters, temperature sensors, pulse generators,etc. can be connected to the main system with common communication protocols.

Types Of Distributed IO 


Variety of signals (both analog and digital) can be measured and controlled by using these modules. Analog values like temperature, pressure, light, etc. or digital signals like buttons, proximity sensors, relays can be easily accessed. Modules produced for measuring special signals such as RTD, Thermocouple,etc. have built in signal conditioners.

Communication Protocols

The communication protocol that modules use depends on the vendor. RS485, Modbus, Profibus, Ethernet, and some vendor specific ones can be found in different vendors. RS485 and Ethernet modules are very common and Modbus/TCP, Modbus/485 are still widely used protocols.

Therefore, some ethernet based modules have wireless connection. They can be configured to connect an access point, and controller computer can reach module through this access point.

Another option is connection to the modules through internet. With the ethernet or wireless ethernet available modules, connection to the module can be ensure through internet by configuring modem or access point properly.

Programmable Automation Controllers (PAC)

Besides the stand alone modules, there is another option which provide user more strong distributed IO with an operating system. PAC is a small computer which can run RTOS (Real Time Operating System), Windows CE or embedded Linux.

PACs have multiple IO slots, therefore user can configure a system by installing different IO modules. HMI devices can be connected to PAC, however, it is not necessary. The IOs can be added also by connecting other distributed IO modules through communication ports stand on PAC (such as RS485, ethernet, etc).

Final Words

Distributed IO has a lot of benefit where there are far distances between controller and actuators/sensors and high communication speeds are not needed. Almost every automation company has variety of distributed IO solutions. And it is easy and fun to set up a data acquasition and control system even in very large areas.

Industrial Automation Layout

An industrial automation system basically has a layout like on the left picture.

The top most part is the HMI (Human Machine Interface) where operators interact with the all automation system. It may consist screen, keyboard, LEDs, buttons, etc.

The second part is the Industrial Communication. HMI must communicate with the whole system to send control signals and receive information. On the physical layer, Industrial Ethernet, Serial Communication like RS-232/485/422, CANBus, etc. And Modbus, Fieldbus, or other protocols can be used as communication protocols between HMI and/or DAQ devices.

At the bottom part there are DAQ (data acquisition and control) devices. This devices control and measure outside world via actuators and sensors. They can control relays, motors and they can measure analog signals, read button status, count.

There are many companies that produce automation products. Automation engineers bring together this products together and set up a full automation system. All we need is to define system properly.

Industrial Automation with Micro Devices

Industrial automation is a huge area limited by the imagination. It is simply measuring and controlling the world with minimum aid of the humans. You can apply automation to a small coffee machine or an automotive factory.

We bring together small components to set up an automation system. In a factory automation, we use robots, conveyors, colour sensors, computers, PLCs, etc. There can be millions of components in a big automation system.

We start to build system from the top. Then, we go through bottom. But what is there in the most bottom? Yeah, pure electronics!

On MicroAutomate website and on this blog, i will dive inside of the electronics in automation. I hope one day they will become useful.