Midwest Manufacturing News • July 2016 • Monitoring Solutions For Safety Brakes

As the amount of networking between people, processes and machines increases, the requirements on the individual components of a driveline also rise. “Mayr Power Transmission has therefore risen to the current challenges set by the Industry 4.0 and has already incorporated into its range intelligent products that can communicate with the superordinate controls,” said a company spokesperson. The latest developments include an intelligent brake control module, the ROBA-brake-checker, which is not only able to energize safety brakes, but also to monitor them without the use of sensors. It recognizes the switching condition of the actuator and the wear on the brake linings, and thus detects safety-critical conditions prior to their occurrence. Any changes in the braking torque can be instantly detected and countermeasures initiated for functional and operational safety.

The module ROBA-brake-checker serves to operate safety brakes at reduced power while simultaneously monitoring their switching condition. It is designed for an input voltage of 24 V or 48 V DC, and can control brakes with a coil nominal current of 10 A or 5 A. In comparison to the previous fast acting rectifiers, the new module is characterized by its higher performance and also by a larger input voltage range of 18-30 VDC or 42-54 VDC and a controlled output voltage at reduction. In addition, a higher cycle frequency is possible. The module ROBA-brake-checker detects when the brake condition changes, i.e., whether the armature disk has been attracted or released. The module emits the respective switching condition of the brake via a signal output. With the ROBA-brake-checker, the switching condition of safety brakes can therefore be recorded in machines and systems even without the usual microswitches or proximity sensors.

The module functions without mechanical contacts and is wear-free, independent of the cycle frequency and count. The additional wiring and possible sealing of switches and sensors is no longer required. In addition, it is possible with the sensorless condition monitoring to adapt the overexcitation time automatically if required. Here an integrated automatic system regulates the voltage to the set lowering voltage after a brake-specific overexcitation time. Using a DIP switch, the automatic system can be switched off, after which it is possible to set certain, specified values manually.

Through the comparison of tightening current and holding current, the module ROBAbrake- checker is able to detect a possible wear reserve or line breakage, or, if applicable, to detect unpermitted heat-up. In this way it can reveal safetycritical conditions and errors prior to their occurrence. The monitoring module can be used for a wide range of ROBA-stop brakes and can be integrated into existing systems. With its compact dimensions of 30 mm in height, 69 mm in width and 73.6 mm in length, it can easily be integrated into control cabinets.

For applications that require braking torque control in addition to condition monitoring, Mayr Power Transmission provides the braking torque control module ROBA-torqcontrol. It features the properties of the ROBA-brake-checker and is additionally able to change the level of braking torque during operation through the targeted influencing of current and voltage. In this way, devices and machines can be evenly and gently decelerated. The module ROBA-torqcontrol allows control circuits to be constructed and movements to be braked intelligently.