High temperatures, humidity and vibrations are the enemies of electrical and electronic components. If, for example, the temperature in the control cabinet rises due to insufficient cooling, malfunctions or even failures become increasingly likely. In the worst case scenario, an entire production line can come to a standstill - with considerable financial consequences. Causes of faults that only occur sporadically are particularly difficult to rectify, for example in the event of brief temperature increases. For example, it is possible that the sun only shines through a hall window every few days at midday and heats up the control cabinet even more. In such cases, control cabinet monitoring can be very helpful, as the service technician has meaningful data at his disposal with which he can detect such events.

Plug in and you're done

However, installing an appropriate measuring box in the control cabinet is time-consuming. The hardware must be purchased, wired and parameterized so that the monitoring solution can communicate with the control application. However, there is an easier way.

The X20CMR011 I/O module from B&R is mounted on the DIN rail like any other module. This is possible for both new and existing machines. No additional wiring or hardware is required. In large control cabinets, additional modules can be placed in strategic locations if required. They are connected to the control system via a bus controller.

Data logger on board

The monitoring module measures temperature, humidity and also vibrations via an integrated acceleration sensor. The data can be read out by the application at any time, for example for service entries or messages. Certain data can also be stored in the module's internal memory, for example minimum and maximum values, as well as the time spent in a certain value range. The internal memory of the modules works without a battery and is therefore maintenance-free. The values are retained even if the control unit is replaced.

The module also offers the option of connecting external sensors to two digital inputs, for example door contacts. This makes it possible to track whether the enclosure door is open. Two PT1000 inputs are available for external temperature sensors. A warning light, for example, can be connected via a digital output. This allows you to see at a glance if excessive temperatures, humidity or vibrations could damage the electronics in the enclosure.

Inexpensive monitoring tool

The author: Andreas Hager is product manager for control technology at B&R.

© B&R

Enclosure monitoring is just as interesting for the machine or system operator as it is for the machine manufacturer: for example, they can track the conditions under which their enclosures are working, i.e. the actual temperatures at the location, the air temperature or how often the enclosure door is opened. Preventive maintenance measures are just as possible as future product optimizations. Last but not least, it is easier for the machine manufacturer to deal with complaints. The stored data can be used to determine if there has been an operating error - for example, if the enclosure door has been left open and the air conditioning has not worked properly as a result. The monitoring module can be used to reject unjustified claims.