Function blocks
44 Function blocks for TwinSAFE logic components
3.4 The function block ESTOP
3.4.1 Functional description
An emergency stop circuit with up to eight emergency stop inputs (EStopIn1-EStopIn8) can be realized
with the FB ESTOP. Each of the eight inputs can be parameterized as break contact (0 requests the safe
state) or make contact (1 request the safe state).
The first output (EStopOut) goes immediately, and the second output (EStopDelOut) after a configurable
time delay, into the safe state ("0"), once an input requests the safe state. Each FB output can be linked
to several outputs. Therefore, several outputs that switch off immediately (EStopOut) or with a delay
(EStopDelOut) can be realized with just one FB ESTOP.
To exit the safe state of the outputs, a rising and falling edge must be detected at the Restart input (see
also chapter 3.4.4 Restart behavior). No time monitoring of the restart signal takes place.
Figure 3-13: Function block ESTOP
A feedback loop can be activated for both outputs. The output EStopOut is returned to the input EDM1
and the output EStopDelOut to the input EDM2 through external wiring. The EDM inputs are checked
when the FB changes to the START state (6) (see 3.4.4 Restart behavior). If the EDM inputs don't have
the "1" signal state, the FB ESTOP goes into error state and sets the output error to 1. The error state can
only be exited through acknowledgement via the ERR_ACK input of the associated TwinSAFE group.
Furthermore, the following inputs can be combined to pairs: EStopIn1 / EStopIn2, EStopIn3 / EStopIn4,
EStopIn5 / EStopIn6, EStopIn7 / EStopIn8. The signal states of the two inputs may only deviate from
each other within a configurable discrepancy time. If this discrepancy time is exceeded for an input pair,
the FB ESTOP also enters the error state (FB Error). The error state can only be exited through
acknowledgement via the ERR_ACK input of the associated TwinSAFE group.
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