11.5 System packages

The same path that brings a new software version to the device also offers system packages: small, self-contained changes to the device’s operating system. A package installs a driver, sets up a service, saves the configuration to a USB stick or releases an interface. It thus replaces work that would otherwise require system knowledge and a console – on the device it remains an entry in a list that you tap.

11.5.1 How a package is checked and executed

Every package carries a signature from the manufacturer. The device only unpacks and executes it if that signature is valid and the content unchanged; it rejects a foreign or subsequently altered package. What is protected is the origin: nobody can slip their own package to the device, not even by way of the network.

Before executing, the device shows the package description and asks for confirmation. The package then runs in a window that displays its messages as they appear. If it requires a restart of the user interface, the device performs it itself; if it requires a restart of the whole device, it says so in its messages.

11.5.2 Obtaining packages over the network and by USB stick

Accessible via: Section 11.4, “Software”, “Up-date” key. The function requires #3 Master to be logged in.

When the screen is opened, the device queries the list from the manufacturer. Which connections have to be allowed for this is stated in the answer on cloud and remote access (see FAQ-03, “Cloud and remote access”). If no connection is possible, the key stays grey.

If the device has no internet access, the same path works via a USB stick. All packages – software versions as well as system packages – can also be obtained on any computer, at thermonom.intronik.de. Then:

1. Copy the file with the extension .tar.sig into the top-level directory of a USB stick. Several packages on one stick are possible.
2. Plug the stick into the device.
3. Open Section 11.4, “Software” and tap “Up-date”. The selection now shows the packages from the stick.

If a stick with packages is plugged in, the device offers only its content; the list from the network is left out. The key symbol shows which source applies.

The file name determines where a package appears in the menu: dots become folders. The file System.Overlay.overlayfs-test.tar.sig appears as the entry “overlayfs-test” in the folder “Overlay” inside the folder “System”; a name without a dot sits at the top level. Renaming is permitted and does not invalidate the signature – it is in the package, not in the name.

11.5.3 Internet via a mobile phone

At the machine there is often no network cable, and where there is one, the plant network usually does not lead to the internet. Yet the Thermonom needs both for two things that count when there is a fault: the list of packages and remote support. A mobile phone solves this in two minutes and without interfering with the plant network – a software version is a few megabytes, a system package usually a few kilobytes.

The package install-usb-tethering has to be executed once; after that the path is always available. In operation then:

1. Plug the phone into the device’s USB socket with a USB cable.
2. Switch on USB tethering on the phone (Android: Settings, Network and internet, Hotspot and tethering).
3. The device obtains its address automatically and uses the phone’s connection. No restart, no input on the device.

After the session, unplug the cable and switch tethering off on the phone. The setting remains in the device and takes effect again next time.

11.5.4 Saving configuration and recipes

Device settings, recipes and the network setting of a device can be saved completely to a USB stick and transferred to a second device. This is worthwhile when setting up a second, identically configured system, before an intervention with an open outcome, and as a backup that is not inside the device. The answer on transferring the configuration describes the procedure step by step (see FAQ-10, “Transferring the configuration”).

11.5.5 Enabling remote support

A screen is hard to describe over the phone. With remote support, customer service sees the same screen you see and can operate it – this shortens a clarification from an hour of describing to a few minutes of watching. You always grant the release on the device, and access is only possible while it is running. The answer on remote support describes the procedure (see FAQ-13, “Remote support”).

11.5.6 Network, interfaces and accessories

These packages do not belong in every device, because each of them presupposes something not every device has: a radio adapter, a card reader, a remote station. They are therefore installed when needed instead of occupying space and services in the device that nobody uses.

11.5.7 Network capture for the system interface

If the coupling to the system is disturbed, it is usually unclear which side causes it. The system computer reports a timeout, the Thermonom reports nothing, and both parties are right from their own point of view. A capture of the network traffic ends this situation: it records every request and every response with a time stamp – which register was read, what came back, whether anything arrived at all and how long it took.

The captured ports are those of the system interfaces: Modbus TCP and OPC UA (Chapter 12, “OPC UA interface”). The resulting file is a common capture format and can be read with widely used tools. It is the information with which customer service can trace a protocol fault without being on site – send it together with the time at which the fault occurred.

11.5.8 Maintenance mode and write protection

A hot runner controller is switched off by someone flipping the main switch, not by shutting down an operating system. A computer that loses power at the wrong moment can damage its file system in the process – and would then stand still while the mould cools down.

The Thermonom is therefore built so that its operating system is write-protected. The delivered system state is never changed during operation; every change – an installed driver, a log file, a service – ends up in a separate layer above it, the overlay. Both of the things that make this method valuable follow from that: the tested base state is still present, and a device switched off abruptly comes back up. Settings, recipes, logs and licences are kept separately in a writable area – a recipe therefore survives every restart.

The four packages follow exactly from this. A change to the system initially lies in the overlay layer: the device works with it, but the base state does not know it. Whoever wants to keep it merges it with the base state; whoever wants to get rid of it discards the layer. And whoever has to work on the system itself lifts the write protection temporarily – that is maintenance mode.

11.5.9 Remedying faults

Three packages remedy states that do not resolve by themselves – a firmware update that got stuck, a damaged file system and an expired root certificate. Each of the three acts precisely there and changes nothing else.

11.5.10 Software versions and licences

A software version brings the user interface, language files and controller firmware together. After installation the interface restarts; the controller firmware is transferred at the next start-up.

The current versions are at the top level of the selection. The folder “Old” contains earlier ones – this makes it possible to reinstall an older version deliberately if a new one behaves differently than expected on a system. The folder “Test” contains preliminary versions that customer service provides for a specific case; they are not intended for general operation.

Packages not described in this section are tools for repair work. Only execute them on the express instruction of customer service.