9 Operation
9.1 Switching state of the outputs
9.1.1 The safe state
The safe state is when at least one of the outputs A1 or A2 (OSSDs) is switched
off (zero-current state: logic "0").
If one of the outputs A1 or A2 is switched off, the subsequent safety-related logic
unit must bring the complete system into the state defined as safe.
9.1.2 The switched state
If the damping element is in the enable zone and if there is no sensor error, both
outputs A1 and A2 (OSSDs) are enabled (logic "1").
9.1.3 Output characteristics
The output characteristics are compatible with the input characteristics to
EN 61131-2 type 1 or 2:
Logic "1"
Logic "0"
*) pull-down current typ. 30 mA
The interface corresponds to interface type C class 0 according to the ZVEI posi-
tion paper "Klassifizierung binärer 24-V-Schnittstellen mit Testung im Bereich der
Funktionalen Sicherheit" (Classification of binary 24V interfaces tested with regard
to functional safety).
9.1.4 Cross faults
• A cross fault between both outputs (A1 and A2) is detected by the fail-safe
sensor and results in the outputs (OSSD) being switched off at the next safety
request. The outputs A1 and A2 remain switched off until the error has been
removed.
• A cross fault between one of the two outputs (A1 or A2) and the supply voltage
leads to switching off the other output (A2 or A1) in case of a safety request.
12
≥ 15 V
≥ 11 V
≤ 5 V
2...15 mA
15...30 mA
leakage current 0.2 mA *)