Logical Block Diagram Of A Safety Function Using The Network; Reset; Ossd Edm (Max Number = 32) - Reer MZERO Installation, Use And Maintenance Manual

Logical block diagram of a safety function using the network

INPUT MZERO_1

RESET

This operator generates a system Reset when there is
a double OFF-ON-OFF transition on the corresponding
input which lasts less than 5 s.
IN
➔
If > 5s, RESET is not generated.
➔
It can be used to reset faults without disconnecting system power.

OSSD EDM (max number = 32)

The OSSD EDM (External Device Monitoring)
operator allows to control an EDM feedback related
to a safety output using a generic MZERO input.
The Output can only be connected to one safety
output functional block (OSSD).
This output functional block must have the K
external time monitor deactivated.
•
OSSD output connected downstream is at
high level (TRUE) -> the Fbk_K signal must be
at low level (FALSE) (within the set delay) and vice versa.
•
If the delay is not respected, the Output of the OSSD EDM block goes to low level (FALSE)
and the anomaly is signaled by the flashing of the CLEAR led corresponding to the OSSD in
error.
If Enable Error Out of the connected output is selected, this output is set to high level (TRUE) when
an external FBK error is detected (example: exceeded the external time K).
Example of OSSD with correct Fbk signal:
In this case ERROR OUT=FALSE
8541403 • 19/07/2021 • Rev.1
STAND ALONE PROGRAMMABLE SAFETY CONTROLLER
MZERO_2
LOGIC (NETWORK)
t
t < 5s
MZERO_3 MZERO_4
Example of OSSD with incorrect Fbk signal
(External K delay exceeded):
In this case ERROR OUT=TRUE
OUTPUT
105