Table of Contents

SSH access

All Unipi devices include a full-featured ARM-based Linux environment, which is accessible via a Secure Shell console after following the steps below. This allows the users of Unipi devices to fully leverage the incredible versatility provided by open-source software packages.

Unipi Edge / Patron / Gate

Unipi Patron controllers and Unipi Edge / Gate devices have an internal SSH server. This server is enabled by default for all the most current OS images that we provide for these units. The exception is the Mervis OS image, which has SSH disabled. Instructions for enabling SSH can be found in the leaflet supplied with the unit or below. After enabling the server, it is then possible to connect to the PLC through any SSH client in the local network. The following instructions are intended primarily for users who are not yet familiar with SSH.

Connecting to the service interface, enabling the SSH

The first step is to enable remote access to the SSH internal server. This configuration is available in the service interface accessible by the following methods:

1) In a local network (with DHCP):

  1. Connect the unit to your local network, plug in the power supply and wait at least for a minute before the unit boots and gets an IP address from DHCP. After that unplug the power supply
  2. Press and hold the Service button located (with exceptions) in the upper row of the connector labels to the left from USB port labels or next to the eth0 ethernet interface
  3. Plug in the power supply. After few moments the unit will switch to the service mode indicated by the slow flashing of all diodes in section 1 or on the whole unit depending on product line (except PWR and RUN)
  4. Now you can release the Service button.
  5. You now need to get the unit IP address. You can obtain it either from the DHCP server or using a suitable application such as Advanced IP Scanner → user manual

2) Direct connection to the unit (without DHCP):

  1. Connect to the unit using a network cable (RJ45)
  2. Press and hold the Service button located (with exceptions) in the upper row of the connector labels to the left from USB port labels or next to the eth0 ethernet interface
  3. Plug in the power supply. After few moments the unit will switch to the service mode indicated by the slow flashing of all diodes in section 1 or on the whole unit depending on product line (except PWR and RUN)
  4. Now you can release the Service button.
  5. Set the PC IP address to 192.168.200.100, mask 255.255.255.0
  6. The unit's IP is now set to 192.168.200.200

Enter the IP address into your browser's address tab and confirm. Upon loading the service interface the following screen with multiple buttons should appear:

To enable the SSH server first, click Enable ssh in the Settings category, and when the successful enable message appears, click Restart System in the upper right corner.

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Attention:
Due to security reasons enable/disable SSH buttons are not available in Mervis OS 2.7.17.0 and newer

Unipi Neuron / 1.1

All up-to-date OS images provided for Unipi Neuron and Unipi 1.1 controllers have SSH enabled by default except for the Mervis OS image. Password must be insert to SD card before connecting to the unit using SSH. See Passwords.

Selecting a suitable communication software

There are many tools that can be used to connect to SSH servers. For this tutorial, we recommend using PuTTY

Connect via SSH using PuTTY

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

To connect to the controller 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.

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Attention:
SSH must be enabled before connecting to a controller running Mervis OS.

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

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).

After launch, the following window will appear:

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.

A prompt to enter login and password will be displayed
Login is always: unipi. Password is randomly generated and can be found on the information label on site of each unit. This password is stored in HW and it is set when new clean image is flashed from manufacturing or by using Os images provided within this manual.

  • Login: unipi
  • Password: Written on the information label

If no password can be found on the information label refer to the article about Passwords. More detailed information about passwords can be found at that article.

After the first login on new OS, password change is required. This new password should be used for that system from that point on. When creating a backup of the OS and uploading it the newly set password will be used instead of that which is given on the information label.

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Note:
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:

Securing the OS (SSH)

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Attention:
Securing the operating system is always needed to prevent unauthorized access to the Unipi units. Using a non-secured OS may lead to unauthorized tampering that can stop or limit the system's operation. In the worst-case scenario, it may also cause damage to the connected technologies or endanger personnel on the installation site.

For these reasons, it is important to properly secure the system each time a new project is created. Alternatively, you can disable the SSH access completely.

As the connection is provided by the SSH protocol, it is necessary to know the IP address or the mDNS address of the device and have an SSH client installed on your PC or tablet. Among the most frequently used clients for Windows OS is the PuTTY application - user guide and default passwords are available here.

Before continuing, make sure you are logged in as the right user (for example “unipi” on our Base OS). You can verify this by whoami command. 

unipi@S103-sn999:~$ whoami
unipi

Now letps proceed to change the password by entering the following command: 

passwd

A prompt to enter and confirm the current and new password will be displayed. If everything is set correctly, the following message will appear: 

Changing password for unipi.
Current password:
New password:
Retype new password:

The entire process is depicted below (the password is not visible during its entering): 

unipi@S103-sn999:~$ passwd
Changing password for unipi.
Current password:
New password:
Retype new password:
passwd: password updated successfully


Was the password change unsuccessful?
If the password change fails, the following message will appear: 

passwd: Authentication token manipulation error
passwd: password unchanged

To solve this issue, try to enter the command below and then repeat the password change process. 

sudo mount -rw -o remount /

Next, it's good practice to sync the changes on the storage (eMMC or SD card). This can be achieved by the sync command: 

unipi@S103-sn999:~$ sync

You can now logout from your SSH session, reboot the PLC or power it of and on and login back to verify that the password has been sucesfully changed.

If the password cannot be changed even after entering the command, please contact our technical support.