Control cabinet monitoring – protecting and monitoring components

Maximum efficiency and process reliability: The benefits of control cabinet monitoring

Monitoring control cabinets with sensors and moneo offers numerous advantages across a wide range of applications:

• Early and automatic fault alerts: Continuous monitoring allows faults to be detected early and reported automatically, enabling a rapid response.
• Reduced energy costs: Optimised cooling and heating systems help reduce energy costs. At the same time, maintaining optimal ambient temperatures extends the service life of control cabinet components.
• Prevention of damage and unplanned downtime: Monitoring humidity and temperature fluctuations inside the control cabinet helps prevent damage and avoid unplanned downtime. Continuous performance monitoring ensures stable and reliable operation.

Overall, control cabinet monitoring improves process quality while optimising energy consumption and leading to cost savings.

Value proposition

Condition-based and preventive maintenance of control cabinets

To ensure the reliable operation of a control cabinet, it is necessary to monitor various factors that can affect its condition. ifm provides both the sensors for data acquisition and the IIoT platform moneo.

1. Monitoring humidity and temperature

• Relative humidity as a key factor in control cabinets
• Moisture can enter control cabinets through cleaning processes, precipitation or ambient air
• Continuous humidity measurement helps prevent corrosion and short circuits
• Recommended humidity range: 20–60 %
• Temperature is a crucial factor for operational reliability and component lifetime
• Optimal internal temperature: max. 35 °C
• High temperatures shorten the service life of components
• Low temperatures lead to unnecessary cooling costs

2. Temperature monitoring of hotspots

• Hotspots can occur despite internal temperature measurement
• Locally elevated temperatures at individual components
• Typical causes: frequency converters, servo drives, transformers
• Consequences: reduced lifetime, drying out of electrolytic capacitors, system downtime
• Hotspots are often difficult to avoid completely
• Measure temperature directly at the component
• Monitor operating hours depending on temperature
• Goal: early maintenance or replacement before failure occurs

3. Monitoring the 24 V supply

• The power supply is a critical safety factor, particularly in outdoor installations
• 24 V circuits are often insufficiently monitored or only protected by basic safeguards
• Missing protection can lead to power supply overload
• Worst-case scenario: fire in the control cabinet
• Recommendation: reliable monitoring of all circuits to minimise risks

Automated interface management for control cabinets

The integrated solution combing ifm sensors and moneo software offers a wide range of options for monitoring critical components in the control cabinet. If a deviation or threshold violation occurs, an automated email notification can be sent to the responsible staff member. Using various protocols, the data processed in moneo can also be forwarded to third-party systems, including moneo.

System structure

1. Temperature and air humidity sensor inside the control cabinet (LDH292)
2. Temperature and air humidity sensor outside the control cabinet (LDH292)
3. IO-Link master (e.g. AL1350)

How to monitor your control cabinet

For effective monitoring of humidity and temperature, hotspot temperatures and the 24 V supply, moneo must first be installed and the moneo IIoT Core must be activated.

To monitor relative humidity and temperature, an ifm IO-Link multisensor type LDH292 is installed inside and outside the control cabinet. This makes it possible to take ambient temperature effects into account. Both sensors are connected via an IoT IO-Link master (e.g. AL1350 or AL1950). The data is transmitted to the central moneo system via the IoT port of the master once a second. In addition to temperature, the LDH292 sensor also measures relative humidity and outputs it as a percentage. The thresholds for this application are defined according to the data sheets of the devices installed in the control cabinet.

For hotspot temperature monitoring inside the control cabinet, an additional bolt-on sensor (TS2229) is installed directly on the transformer. An evaluation unit (TP3231) converts the analogue temperature signal into an IO-Link signal. Both sensors are connected via an IO-Link master (AL1350). The data is transmitted to the central moneo system via the IoT port of the master once a second. The temperature sensor is also directly linked to an operating hours counter. It counts the operating hours depending on the temperature: The clocking moves faster at higher temperatures and slower at lower temperatures. To monitor the 24 V supply, electronic fuses with IO-Link are installed in the control cabinet. They consist of a feed module (DF2101) and the fuse modules (e.g. DF2212 with nominal current 2 A). Up to eight fuse modules can be connected in series to a feed module, with each feed module consisting of two channels. This makes it possible to monitor and protect 16 circuits with a total current of 40 A. IO-Link communication continuously transfers current information about the fuse modules including:

• Current nominal current
• Output voltage
• Current device status: short circuit, overload, undervoltage
  

The feed modules are connected via an IoT IO-Link master (e.g. AL1350 or AL1950). The data is transmitted to moneo via the master’s IoT port once a second. The tripping of a channel on the fuse module is reported via the device status. This status can then be analysed in moneo, and a notification can be generated automatically. Responsible staff are notified by various means, including email, when a fuse has tripped. The current status is also indicated directly on the respective fuse module by a button with a status LED (green = normal operation, red = fuse tripped due to short circuit or overload). This supports troubleshooting and directly indicates which channel is affected. The fuse can be switched on again directly via the button.