Measurement Electronics SIL / PL

Measuring electronics for functional safety — SIL and Performance Level

When a force or load measurement takes on a protective function — overload shutdown on a press, load limiting on a hoist, presence monitoring in a plant — an ordinary measuring amplifier is not enough. The measuring chain has to be testable, and in the event of a fault it has to move into the safe state by itself.

Here you will find both routes to that:

• SIL3 / PL e with a safety controller. The amplifier puts one bridge signal onto two galvanically isolated outputs, a programmable safety controller compares them and shuts down if they diverge. Redundancy across two channels — the highest level available here.
• SIL1 / PL c with a built-in protective function. A second amplifier, two comparators and a solid-state relay sit inside the device and monitor the bridge independently of the measuring channel. No safety controller is needed for this, and the device remains a usable measuring amplifier with 0.1 % of the measuring range at the same time.

Housing by installation location

For the control cabinet the DR22.5 DIN rail version with IP20, for mounting on the machine the U-CASE 2 field housing with IP65. The series covers both safety levels in both designs.

What goes with it

You will find the matching sensors under load cells & force transducers, the rest of the evaluation electronics under measuring electronics. The basics of SIL and Performance Level, the safety architecture with two independent strain gauge bridges and the figures for plant certification – MTTFd, B10d, DC, FMEA – are explained on the page Functional Safety SIL | PL.