2
2.10
Safe state
The safe state for the module is the zero current state at the output terminals, i.e., the relay
contacts are open (see Section "Safe digital relay outputs (floating contacts)" on
page 2-4).
The safe state can be entered in the following cases:
1.
Operating state
2.
Error detection in I/O devices
3.
Device errors
4.
Parameterization errors
2.10.1
Operating state
In the operating state, the relay outputs can enter states "1" or "0". In general, state "0" is
the safe state.
2.10.2
Error detection in I/O devices
Relay outputs
If an error is detected at a relay output, the affected relay output is disabled ("0" = OFF =
safe state).
Depending on the parameterization, the following errors can be detected at relay outputs:
–
An external load does not pick up (if the alarm inputs are used)
–
An external load does not drop out (if the alarm inputs are used)
The relevant diagnostic message is transmitted to the safe controller (see Section "Safe
digital relay output errors" on page 9-3). For information about which errors are detected
and when, please refer to Section "Connection examples for the safe relay outputs and the
safety-related segment circuit" on page 6-1.
PROFIsafe:
The safe state for the F-Output data is "0".
The safe state is entered by means of passivation (see "Passivation" on page A-2).
WARNING: No communication; loss of the safety function possible due to
undetected accumulation of errors
If there is no communication with the safe controller: Disconnect the module from the
supply voltage after a maximum of eight hours.
If an error occurs on a channel of an output parameterized as "two-channel", the other
corresponding channel also enters the safe state.
2-12
User manual IC220SDL840 -
May 2018
GFK-2734