Safety Function Architecture
The BMXSRA0405 module internal architecture performs the safety function as follows:
1 The state of the relay is continuously monitored by the safety processor, which reads the state of an NC contact mechanically linked to the NO contact, and which in turn is linked to the actuator.
2 The state of the relay command is continuously monitored. Each input is received by 2 identical circuits. The measured values are compared by the safety processor. If values are different, the channel is declared to be not valid.
3 The supply voltage from the backplane is monitored to determine if there is an over voltage or under voltage condition.
4 The companion chip supplies the safety processor, continuously diagnoses the safety processor, and monitors backplane voltage.