SISO3 is a signal isolator that electrically isolates the intrinsically safe circuit from non-intrinsically safe circuit such as a data acquisition system, e.g. AMSY-5 or AMSY-6. A SISO3 is required if an ISAS3 is installed in an hazardous area according to ATEX. The SISO3 itself can be installed in ATEX zone 2 environments. SISO3 requires an enclosure guaranteeing ingress protection class IP54.
SISO3 limits the power, voltage, current and pulse energy supplied to the integral ISAS3 preamplifier to a safe level even in case of two worst case failures in SISO3. Furthermore, it provides an amplification stage to fully utilize the input range of the ASIP-2 signal processor. It also relays the Auto Sensor Test control pulse to the ISAS3 integral preamplifier.