Everything under control: machine-to-machine networks
The desire for remote control and monitoring of machinery and systems is growing continually. There are many different reasons for this, such as increasing availability, cutting costs or expanding new service business models.
Previously, remote access to machinery and systems was normally facilitated via the fixed line network. However, insoluble problems can occur in this connection, for example, if components to be controlled or monitored are on a mobile device, there is no landline connection on the spot or the later end-customer forbids usage of its local network to the system supplier. Mobile communications may be the best solution in all three cases.
Interest in such machine-to-machine (M2M) solutions is also growing due to the new Operational Safety Ordinance. To enable systems to be monitored from anywhere in the world, all they then need is an Internet connection, which can be set up via a web server. The web server can be integrated both in the lift as well as realised externally via corresponding hard- and software. In addition, a mobile communications router is also needed for communication with the World Wide Web.
Access to mobile communications network
There are several structures for implementing such an M2M network via a mobile communications network. In industry, what is most in demand is accessing the lifts from a control centre. However, SIM cards used in the outer stations normally have no fixed IP addresses via which the lifts could be reached.
Admittedly there are ways to find out the currently assigned IP address, but the IP address changes at particular intervals. Moreover, access to the mobile participants from the Internet is normally prevented by mobile communications providers on account of the lack of security and high costs for the data transmitted.
This complicates the use of the mobile communication network for M2M applications. There are basically two solutions for this: either you request a SIM card with a fixed IP address from the mobile communications provider or you use a VPN network.
SIM cards and their IP addresses
There are SIM cards with a so-called fixed public IP address. However, these are cost intensive and in addition, every Internet user can access the IP address and as a result the lift. This represents a major security risk.
Using a so-called private IP address is a much more affordable solution. In this version you operate in a private network that only permits particular users, thus avoiding the Internet. In addition, this network is also well-protected against unauthorised access.
Secured virtual private network
An M2M network can also be developed with the help of a VPN network. Simple data SIM cards are used for this purpose, which keeps the regular costs down, and an independent VPN network is developed. You set up a VPN server, which the clients, i.e. the lifts, then access. The blockade of the mobile communications providers is evaded in this way, since the lifts develop a secured VPN tunnel to the VPN server.
Communication is possible throughout the entire VPN network through the tunnel. Monitoring of the lift can also be documented and queries regarding the elimination of defects or guarantee claims can be clarified quicker with the assistance of the data regularly transferred. Information on the condition of the lifts is not just provided in the event of malfunctions - rather, it is possible to access all data of the lifts constantly.
Thomas Reimann, CEO Reimann Engineering