Safe brake control (SBC) supplies a safe output signal to drive an external mechanical brake. The brakes used must be “safety brakes”, in which a quiescent current operates against a spring. If the current flow is interrupted, the brake will engage. Control modules frequently include a power reduction feature when the brake is released to reduce energy consumption or brake heating. A safe brake test may be required to detect errors during operation, depending on the risk analysis.
Holding brakes and service brakes are often used on axes with suspended loads. Along with the brake, the brake drive is another key component in terms of the safety function. The safe brake control (SBC) function is generally used to control the holding brake activated once an axis is at standstill.
Safeguarding gravity-loaded axes
Safe control and monitoring of brakes is essential to prevent hazards arising, particularly on gravity-loaded axes. Great risks can arise on vertical movements in automatic production due to gravity, should the power drop out or the braking device fail. As part of the risk assessment it is essential to consider the risks of an unintended fall and define measures to minimise the risk.
Pilz's safe brake control solutions
Pilz offers various solutions: the safety relay PNOZ s50 safely controls two brakes (holding brakes or safety brakes) up to the highest category PL e. PMCprotego DS uses the safe brake test to monitor wear on the brake.
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