Hardware I/O Interfaces


Different connection possibilities are available:

  • USB, Serial or Parallel ports.
  • PCI/ISA Cards.
  • Ethernet, TCP/IP Protocol.
  • Software / OPC / Others...



To connect a serial port input/output device you will need to make a device based on a microcontroller, this is because it will manage the serial port to send the communication messages to the diverse actuators that you connect (relays, opto-isolators, etc..)

EasyPLC allows two different protocol types; byte protocol (with this option you can only use 8 inputs and 8 outputs) or ASCII protocol, where a number is sent followed by a control character to indicate the end of the transmission (control character 13), you can get in this way a maximum of 31 inputs and 31 outputs.

I recommend that you to look at the EasyPLC help to obtain more information. 

Build your own interface for the serial port



You can develop your own interface following the standard characteristics of the parallel port (see connection instructions).

Build you own interface for the parallel port



  • USB OPTO RLY88, 8 optically Isolated Inputs and 8 Relay Outputs.

This card is ideal for interface in all type of PLC (sink or source 24Vdc voltage). Totally compatible with EasyPLC and Machines Simulator.

Card specifications



  • EasyPLC is compatible with input/output devices from diverse makers, and with different system of data capture, using the EasyPLC External drivers.

    For example:

    EasyPLC is compatible with Phidget™ I/O interface cards like:
    PhidgetInterfaceKit® 0/0/4: 4 outputs (digitals).
    PhidgetInterfaceKit® 0/16/16: 16 inputs / 16 outputs (digitals).
    PhidgetInterfaceKit® 8/8/8: 8 inputs / 8 outputs (digitals) / 8 analogic
    And all Phidgets™ analogic-digital interfaces.
    (Phidgets™ and PhidgetInterfaceKit® are trademarked and registered by Phidget™).




With the EasyPLC TCP/IP external driver you can connect two remote computers, for example one in California and the other in Tokyo, and send the sensors/actuators information between them. This way you can manage electronic devices over long distances. 


Siemens Simatic S7 - PLCSIM DRIVER

With this Driver you will be able to communicate your Step 7 logic programs directly with EasyPLC and Machines Simulator without any additional hardware. More info Siemens Simatic S7 - PLCSIM Driver


Using this driver will be possible to communicate with Real or Simulated PLC's using the standar OPC protocol specifications. For example use it to dialogue with Rockwell RSLogix software. And is included in the registed version!.


EasyPLC can be compatible with any I/O analogical/digital device designed for Windows XP / Vista / Windows 7. With the EasyPLC S.D.K any device compatible with Windows .NET Framework or ActiveX/COM technology can be connected. If you need a specific driver please contact.

IMPORTANT: To use EasyPLC S.D.K. you need the EasyPLC registered version.


EasyPLC has another important characteristic, the Simulated Virtual Interface. With this option it is possible to carry out and to check the programs without the necessity of connecting any hardware.

This modality has multiple applications:

  • Create programs to verify their operation without having concluded the hardware.
  • Verify the programs of other systems.
  • As method of learning PLC languages.
  • Approach to industrial automation.

If this interface is selected, when the PLC is started the window will appear with the available inputs/outputs if it is selected from the EasyPLC notify icon. Pressing on inputs buttons it is possible to force their state to ON/OFF as well as to visualize the state of the outputs.




In this example two serial devices with 8 I/O + Parallel port interface with 8 Out and 5 In + PhidgetInterfaceKit® 0/16/16 are connected.

In total obtained with this configuration:  
33 Inputs and  
40 Outputs


Example Video


 Input/Output Interfaces

The Interface is the electronic device that is connected between the PC and the elements to be controlled (actuators, switches, push buttons, relays, circuits, etc..).
Their mission will be to guarantee the correct isolation between the PC ports and the exterior devices, as well as to send/receive the information to the EasyPLC software about the state of the diverse connected elements.
These interfaces are denominated Inputs/Outputs analogical-digital cards.

You can build your own input/output interfaces yourself or you can acquire commercial devices to connect to the PC ports and to use EasyPLC to manage them.