Communication via SSH using PuTTY

For using SSH you need to know the target PLC's IP address. To detect the address you can follow this guide: Detecting the PLC's IP address.

To connect to the PLC we will use the PuTTY. You can use other SSH applications as well, but PuTTY is the most suitable for Windows OS. The program can be downloaded in the Useful tools.

Install the downloaded PuTTY following the installer's instructions. After that, launch the program through putty.exe (its default location is C:/Program Files/PuTTY).

Upon launching the following window will be displayed:

Enter the IP address into the Host Name tab and check if the Connection type is set to the controller's SSH. Then click on Open. A security dialogue window will appear for the first time. Click on “Yes” to display the SSH terminal's command line.

The next step is to enter your login:

  • Login: unipi
  • Password:

Login has a time limit. If the limit expires, login will be no longer possible and you need to restart PuTTY and log in again.

The password is entered as an invisible text, eg. if the cursor does not move when entering the password, it is not an error!

After a successful login to a Unipi PLC this screen will appear:

Upon finishing the configuration you need to disable the SSH access or change the user password!

Changing the SSH access password:

User password can be changed using the passwd command.

unipi@S103-sn16:~$ passwd

After entering the passwd command a prompt for entering current password will appear. The next step is to enter the new password and then re-enter it for confirmation.

Changing password for unipi.
Current password:
New password: 
Retype new password:
passwd: password updated successfully