Reduced expenditure for IT damage in the ex-area

SCADA systems enable the operation of machines from a control room. However, they cannot completely replace the operator on site in the hazardous area, because the operator can also perceive information that is not recorded by sensors and is indispensable for maintenance and servicing. Ex-proof panel PCs integrated into the SCADA system make it possible to control the machine on site as well (Fig. 1). In most cases, panel PCs with Windows as the operating system are used for this purpose. However, especially in hazardous areas, the immediate environment of the machines is often very harsh and extreme - either because the place of operation specifies such conditions (open sea, sunlight, strong temperature changes), or because the machine itself generates waste heat, vibrations or shocks, for example. Not every Panel PC can withstand this for long, and even the most robust ones will break down at some point - always at the worst possible time, of course. Every second of downtime costs money and endangers the production process or even human lives due to the explosive atmosphere. So a replacement for the defective PC must be found as quickly as possible. Modern human-machine interfaces and networks strive for completely fail-safe communication in order to enable permanent control of the production process from the operating station - this is subsumed under the keyword "Ex 4.0".

Backup & Restore saves time - also for OEMs
In the event of an operator station failure, there are several possible breakdown recovery strategies. Naively, the simplest method is to reinstall a new or replacement device from scratch to match the machine and

In the event of failure of an operator station, several strategies are possible to eliminate the breakdown.

configure. However, it can take half a working day to set up the complete software. This means that the failure can be extremely expensive depending on the application. It would be more intelligent to set up a Panel PC once and create a backup of it. If the worst comes to the worst, this backup can then be "restored" on a replacement device (Figure 2). Because the stored data is simply copied automatically, this is much faster than manual installation and setup. Furthermore, once the process is started, it continues to run independently, effectively keeping the operator busy for only a few minutes and allowing them to do other work while the restore is in progress. OEMs also benefit from faster installation of the devices to be shipped through such a solution. This is because the same software is often installed on the same hardware, so that an image created once can be copied to a large number of devices. Since the copying process runs automatically, the operator can already start the same process for the next devices while the first panel is "restoring". Parallel processing speeds up the installation process again compared to manual installation.

Do not forget settings - even without a network connection
The backup in the presented strategy so far only contains the freshly set up device. Settings or generally the data that accrue on site and are stored on the Panel PC itself are still lost in the event of a defect. This still causes unnecessary effort despite the quick readiness of the replacement PC. An optimization of the automation of the device setup is the regular backup of the memory to a server. If the devices used are backed up regularly, the last backup can simply be restored to a functioning device in the event of a defect. The regular backup can also be automated via the network, e.g. at night or during breaks when the devices are not in use anyway. To restore the backup and thus overwrite the internal memory, you have to boot the device from an external memory. Not every PC can boot over the network, so the restore needs a mobile storage, e.g. a USB stick. This also provides storage space for backups, so that backups and restores can be performed on any panel PC even if the network infrastructure is poor.

USB recovery stick solves two problems at once
At panel PC manufacturer R. Stahl HMI, the devices produced used to be installed manually in a laborious process. The company's developers looked for a cheaper, more time-efficient alternative and ultimately developed a USB recovery stick.

Regular backups can be automated over the network.

developed itself, as nothing suitable could be found on the market (Fig. 3). Their recovery software PE is also used in-house to record the devices with the software requested by the customer in a time-efficient manner before delivery.

This automated solution for backing up and restoring Panel PCs consists of a robust USB stick, which is also available in explosion-proof versions for use in potentially explosive atmospheres. The stick contains a Windows PE bootable directly from it (see Windows PE technical box) and the PE recovery software. In this way, the operating PCs can also be directly restored in the immediate vicinity of machines with potentially explosive operating materials. For an additional charge, the USB stick also contains the backup software. The logic behind this is obvious: the backup software is used at scheduled times and is therefore only needed a few times to create backups. In contrast, the less expensive recovery-only sticks can be kept wherever the Panel PCs are used, so that operators can react as quickly as possible if the worst comes to the worst. The sticks and the software have already proven themselves in practice and are constantly being further developed on the basis of practical experience.