In this interview, Andreas Merz from Product Management at mayr® power transmission explains how sensorless, networked brake monitoring can support efficient and proactive machine maintenance
mayr® power transmission offers solution concepts for the proactive maintenance of electromagnetic safety brakes based on permanent inspection. These brakes are predestined components for safety and system availability, and permit conclusions to be drawn regarding system operation for plannable maintenance. Here, the focus in placed on the ROBA®-brake-checker module, which is not only able to monitor and supply brakes without the use of sensors. In an advanced version, it also provides data, thus ensuring intelligent safety. This means that processes can now also be evaluated, anomalies in processing procedures can be detected quickly and conclusions can be drawn from complex interrelationships. For users, this means plannable and cost-effective maintenance and maximum system availability.
Safety becomes visible
The ROBA®-brake-checker module works without sensors. It detects the movement of the armature disk through extended analysis of current and voltage, and knows what condition the brake is in. In addition to the switching condition, temperature and wear, the ROBA®-brake-checker also monitors the pull-in distance or tensile force reserve, i.e. whether the magnet is still able to attract the armature disk. With the new module, substantially more parameter are thus depicted during monitoring than with microswitches and sensors. On reaching the tensile force reserve, the ROBA®-brake-checker emits a warning signal early enough so that a certain operating time for the brake is still possible.
Mr Merz, which data does the ROBA®-brake-checker module generate through the extended analysis of current and voltage?
Andreas Merz: With the ROBA®-brake-checker module, data regarding the switching time, current, voltage, resistance, performance und relative attraction current can be generated. This permits conclusions to be drawn regarding critical brake operating conditions. If the resistance is detected as being on the increase, conclusions can be drawn as to the coil temperature, which also increases. If the temperature gets too high, the brake may not be able to release anymore. If the separation time (release of the brake) and the attraction current increase simultaneously, then this is an indication of wear.
More data für more safety: Why does this data represent added value for customers and how can we use the knowledge gained?
Andreas Merz: In the advanced version, the module is equipped with an additional circuit board with a customer-specific interface (e.g. optical, WiFi, IO Link, OPC UA etc.). Using an evaluation programme, the customer can see whether everything is running smoothly or whether there is work that needs to be done. In collaboration with the customer, the issued data is integrated into their evaluation system – with regard to the individual project and the requirements of the respective application. This means substantial added value. If, for example, the limit temperature is reached, this is an indication of damage to the brake, of brake failure or even incorrect dimensioning. In the advanced version, the module is equipped with an additional circuit board with a customer-specific interface (e.g. optical, WiFi, IO Link, OPC UA etc.). Using an evaluation programme, the customer can see whether everything is running smoothly or whether there is work that needs to be done. The ROBA®-brake-checker also shows when critical wear values have been reached. This permits preventive maintenance, which in turn ensures higher system availability. Over and above this, the data output via an appropriate interface facilitates the integration into a remote maintenance system. This reduces service times and costs.
Temperature progressions and changes in parameter across a product’s lifetime are also made visible. In the case of previous solutions, such as contactless release monitoring, users are only able to see the failure or destruction pattern, but do not know how the error occurred. Using the ROBA®-brake-checker, on the other hand, progressions are made visible and error analysis can be used and even transferred onto other user systems. All this data from malfunctions and normal operation thus supply valuable input for future improvements and optimizations.
The monitoring of the pull-in distance or tensile force reserve, i.e. whether the magnet is still able to attract the armature disk, serves the assessment of risks as well as the monitoring of switching times. Changes to the switching times have effects on the braking distance. In particular in the case of vertical axes, short stopping distances and times are important. The brake switching times are decisive for the braking distance. In the time of free fall until the brake closes and retardation occurs, the mass additionally accelerates – in some circumstances to such an extreme extent that the permitted values for the brake are exceeded. The planned switching times must be maintained over the entire lifetime of the brake. For this purpose, the ROBA®-brake-checker acts as a reliable switching status control.
Using your solution, you support users on the path to future-oriented machine maintenance and repairs. What is the additional expense for the user?
Andreas Merz: We are the only company to offer a standardized, intelligent solution for the sensorless monitoring of electromagnetic brakes with our ROBA®-brake-checker. Users are able to integrate the module easily and quickly into machines and systems without having to intervene in the ‚converter‘ or ‚control‘ components. Our brakes can also be easily retrofitted into existing systems; only a small modification to the wiring is required. Therefore, users are not taking any risks as they are not required to validate limit values and data themselves. We supply the ROBA®-brake-checker ready for installation and test all values beforehand. For users, this means a ‚plug-and-play solution‘, so to speak. Designs with extended data exchange are aligned specific to individual projects in close alignment with the customer. In future, we will offer the module in a new, modern and functional design.