Compact Control Cabinets Ensure High Information Security

To monitor access to control cabinets and keep an eye on temperature values, the distribution system operator e-netz Südhessen AG uses compact cabinet guards from Turck

Electricity, water and gas are considered to be constant in Germany, and disruptions to supply are the exception. This is due, among other things, to regional distribution system operators such as e-netz Südhessen AG, which operates electricity and natural gas networks for electricity and gas suppliers. Since high plant availability is the priority for e-netz Südhessen, the Darstadt-based company itself monitors the condition of control cabinets in decentralized facilities such as transfer stations or biogas plants. There, Turck's IM12-CCM cabinet guards can detect when a door is opened or when temperatures are too high.

Information security until the door is opened

As a network operator, e-netz Südhessen counts as part of the critical infrastructure (KRITIS). For these organizations and institutions deemed to be of great importance to the community, the Federal Ministry of the Interior has defined strategic content to ensure high availability and security – for example of IT systems. Based on this, the Entega subsidiary defined specific requirements for internal information security. "We wanted to be able to monitor entrance doors and control cabinets in all gas pressure control and measuring stations," said Jürgen Nagel, who is responsible for the electrical system in the gas and water supply plants of e-netz Südhessen. When was a control cabinet door opened at which location? This information is expected to reach the control center without the need for complex electrotechnical expansions in the decentralized stations.

The IM12-CCM is simply mounted on the DIN rail and then monitors temperature, humidity and door closure
e-netz Südhessen AG adapts the supplied natural gas to the conditions of the local pipelines
Simple retrofitting the IM12-CCM: The low installation and commissioning costs convinced the specialists
Insecure door contacts that were costly to install were not considered for the cabinet guarding system
Jürgen Nagel | e-netz Südhessen AG

IM12-CCM replaces costly roller switches

"I did not think that door contact switches were reliable enough, and the costs would have been too high for roller switches," said Nagel, describing the selection process. "With these, you have to drill holes into the cabinets, bend the metal in part or work with small tools." The tests with Turck's IM12-CCM cabinet guard were more successful. This compact device for direct DIN rail mounting has internal sensors that measure three values: temperature, humidity and the distance to the door. "The device is ideal for our purposes: clip it in, apply two wires and voltage, route two wires to the PLC – and you're done."

e-netz Südhessen now uses three interconnected cabinet guards in its largest transfer station. Using reed contacts, the two downstream devices transmit their signals to the primary IM12 CCM, which in turn forwards the information to the PLC. This notifies the control center employees that a control cabinet door has been opened on site in the station. This simple possibility of retrofitting control cabinets with an internal monitor set a precedent at the Darmstadt-based company. In the meantime, the electricians are also using the devices in district heating and biogas plants.

Temperature measurement

Most gas transfer stations and district heating plants already have air conditioning technology, which prevents overheating of the electronic devices. Components installed in the control cabinet include frequency converters or power supplies for pressure transmitters and temperature measurement. Isolation amplifiers are also present, and e-netz Südhessen has been relying on Turck for these for more than 30 years. Nevertheless, not all stations are air-conditioned yet. In one of the transfer stations, Jürgen Nagel therefore also uses the temperature measurement provided by the IM12-CCM. "The control cabinet is located in the heating room, where it can become very warm despite insulation. Especially with a PLC or a power supply, I prefer it to be a little cooler."

Easy retrofitting of condition monitoring

Condition monitoring is not only required for machines and storage areas, but also for control cabinets. This is demonstrated by the information security management system of e-netz Südhessen AG, which uses Turck’s IM12-CCM to monitor the door closure of control cabinets in decentralized plants and thus to draw attention to unauthorized access. The sensors installed in the device for measuring temperature and humidity also pay off in cases where unstable climatic conditions jeopardize the availability of electronic devices. For the e-netz specialists, the effort involved in commissioning was an important factor in the retrofitting. Turck’s IM12-CCM impressed them through its simple assembly and uncomplicated teach functions.

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