BECKHOFF TwinSAFE - Manual (Page 122)

Circuit examples
120 Application Guide TwinSAFE
2.20 Drive option AX5801 with stop function SS1 (Category 4,
PL e)
By activating the emergency stop button inputs EStopIn1 and EStopIn2 of FB “ESTOP” are switched to
state “0”, resulting in outputs EStopOut and EStopDelOut of FB “ESTOP” being switched to state “0”. As
a result, a quick stop command is issued to the PLC and therefore the AX5000 via EtherCAT. The output
EStopDelOut of the “ESTOP” FB ensures that, after the expiry of a specified delay time (in this case e.g.
1000 ms), the 24 V supply of the safety option AX5801 is interrupted and the internal relays of the
AX5801 are thus de-energized. The two channels (motors) are switched torque-free via the internal
switch-off paths of the AX5000.
Testing and checking for discrepancy are activated for the input signals. The testing of the outputs is also
active. The relays of the 4 AX5801 option cards are wired in parallel to a safe output of the EL2904. The
feedback loops are wired in series to a safe input. The restart signal is wired to a non-safe input.