The ProLine P 22400 passive standard signal isolator from Knick is certified for applications with safety integrity level SIL3 in accordance with EN 61508. The safety functionality of the passive isolator consists of the high-precision, linear transmission of 4 to 20 mA signals with a transmission error of 0.08 % F.S. According to the manufacturer, a high level of safety can also be achieved in a single-channel structure and without diagnostics: For example, sensors and actuators in safety circuits can be connected directly to the standard signal isolator without complex evaluation equipment for redundant structures. The mechanical design of the device is so robust that it is also suitable for marine applications, it is insensitive to EMC interference and is protected against electric shocks by reinforced insulation up to 600 V (AC/DC). With a design for operation at ambient temperatures of -40 to +85 °C, the passive isolator is also suitable for extreme conditions.