Increasingly stringent regulations are forcing a wider range of equipment and devices to comply with the safety levels SIL2 (as per IEC 62061) and PLd (as per ISO 13489). This means using components that have been certified to at least this safety level. DIS Sensors, in the Netherlands and Belgium represented bij Rotero, recognizes this need, and has extended the QG series of sensors with CANopen safety sensors with built-in redundancy for safety-critical applications. The new certification applies to QG series inclinometers and accelerometers.
Inclinometers measure the angle of inclination in one or two axes. DIS inclinometers are based on robust MEMS technology. Thanks to their modular design, these sensors are easily adapted to meet specific requirements. It is also possible to adjust the sensors as required, by means of CAN commands.
Accelerometers measure acceleration in 1, 2 or 3 axes. These sensors are likewise based on MEMS technology. The difference with the inclinometers is the wider bandwidth, enabling this type to measure much faster movements, and with greater precision. These sensors are therefore suitable for applications such as vibration measurement for maintenance purposes, or for active vibration compensation.
Safe variants: SIL2 and PLd
The announced availability of ‘safe’ variants of the QG sensor series has greatly increased the range of potential applications. Moreover, the components are certified as compliant with both SIL2 and PLd. Each of these standards aims to quantify the relative level of risk reduction of a machine or installation. Given its relatively simple approach, most machine builders prefer the PL system (Performance Level in as per ISO 13489). SIL (Safety Integrity Level as per IEC 62061) has more variables and complex formulas, but it is more comprehensive, especially in the area of documentation and data registration. This can be beneficial to management aspects for example, or the compilation of a functional safety plan; information required by more and more companies.
The safety is provided by features such as the redundant (dual) functionality, communication via the CANopen Safety Protocol EN50325-5 (CiA304), and continuous verification of correct operation of all components.
All models are available in a standard housing of reinforced plastic, or optionally a stainless steel housing. In addition, the sensors are supplied standard with a 1 x M12 terminal (IP67) or a cable exit gland (IP68). The sensors can also be supplied with 2 x M12 terminals to enable a looped network design.
