Wieland samos - Reset Function and Feedback Circuit Monitoring

Glossary
© 2010 Wieland Electric GmbH | BA000256 | 12/2012 (Rev. I)
47
Reset function
The Reset function defines which (reset) conditions must be fulfilled if, for example, an ON
signal is to be passed on to output Q
START
. All input and muting signals from the base
module and the associated input modules (i.e. of a system group within the samos
system), and the bypass/OR signals from the input modules are logically linked (AND/OR).
The terminal configuration with bridges and feedback circuits is also evaluated (see
below).
An ON signal from the Reset function can only be canceled by an OFF signal from an
input circuit function (i.e. changed into an OFF signal), and is not influenced by enabling,
muting or bypass functions or by feedback circuit monitoring.
& : AND blink ≥1 : OR link
+ : Combination of flipflop + AND link.
Muting : An ON signal is generated only if the output signal of the Reset function Q
Start
has
good state at the beginning of the muting function.
Reset condition / evaluation of feedback circuits
On the base modules there are three control inputs S1, S2, S3 for configuring the control
circuit functions. They can be used, depending on the function, to set starting inhibit,
restarting inhibit, retriggering and off delay (see page 24). Depending on the application,
the configuration is realized using bridges or by connecting the NC contacts of connected
relays/contactors. Together with the module outputs this creates feedback circuits which
allow evaluation of the control states of the respective connected relays/contactors with
positively driven contacts. Evaluation uses one of two different methods depending on the
function (see also page 26).
 The NC contact is connected directly with the respective control input. As soon as the
contact closes the Reset function is activated and it is possible to switch on the outputs.
The configuration is evaluated when the system is switched on. The configuration is
verified before each Reset following a safety event. If a change is detected (e.g.
feedback circuit not closed) the system generates an error message and cannot be
switched back on until the malfunction has been rectified.
 In operation with restarting inhibit the NC contact is connected to the respective input
via a Reset button. The required Reset condition for canceling the restarting inhibit is
only fulfilled if the feedback circuit is also closed.
The feedback circuits that belong to the safety system must be housed in the same
enclosure as the samos system in order to exclude the “Short-circuit to +24 V”.
Reset
Feedback circuit
monitoring
NOTE