Opening the safety gate and quickly readjusting a position or correcting a fault sounds pretty trivial. And it’s true, it is trivial. But only as long as the drives in a production plant have the appropriate safety functions. Thanks to the high basic safety of the LinMot 2S drive systems, such interventions in the systems are possible without any problems at a safely reduced speed. Although plant availability is an important factor everywhere, it is even more important for seasonal products such as irrigation products, as is the case at GARDENA. “With the 2S safety option from LinMot, we are not only safer, but also more convenient when troubleshooting and commissioning the production systems,” explains GARDENA project manager Felix Kaifel, who was recently interviewed.
How “Functional Safety” works
Like Mr Kaifel, many other LinMot customers are pleased to be able to use the C1250 series of servo drive as a 2S variant. They particularly appreciate the fact that the dimensions of the motors have not changed compared to the standard version. No additional hardware is required as all safety monitoring is integrated into the drive itself. In addition to STO (Safe Stop) and SS1, which were already available on the 1S version, the drives now offer Safe Stop 2 (SS2), Safe Operation Stop (SOS), Safe Limited Speed (SLS) and Safe Brake Control (SBC/SBT). The latter Safe Brake Control (SBC) has been extended to include a Brake Test (SBT), which allows the braking effect to be checked cyclically.
Like the drive controller, the linear motors themselves are designed for functional safety, so the three most commonly used sizes are offered with safe encoders. Externally, the 2S motors (stators and sliders) are identical. They do not require an additional sensor and are connected to the drive using the familiar single cable solution for safe drive control.
Safe, fast and reliable communication between the PLC and the individual drives is essential for a functioning safety concept in the machine. The new 2S servo drives therefore communicate with the higher-level control system via various safety bus systems as required. The user can use PROFIsafe via PROFINET and PROFIdrive or transfer protocols via EtherCAT (FSoE), EtherNET IP, POWERLINK and sercos. Alternatively, the safety functions can be activated via the integrated digital inputs.
At a very early stage in the development of the “Safety” products, LinMot brought the globally active, independent certification company TÜV Nord on board. The company supported the product concept with testing services during development and methods for risk minimisation in accordance with the generic standard IEC/DIN EN 61508. The result of this collaboration is the certified compliance of 2S products with all relevant safety standards.
More about “Functional Safety”
Functional Safety im C1251-2S
