Technical data
ABB Safety Handbook | 2TLC172001C0202 5/6
5
The dynamic signal consists of a square wave that is
transmitted through the safety circuit. The signal is
inverted at each safety component and is monitored 200
times per second by Vital or Pluto.
The dynamic signal is transmitted as single channel throug-
hout all the protection in the same safety circuit between
input terminals T1 and R1. If a protection breaks, the dyna-
mic signal is not transmitted which is detected by Vital which
breaks its safe outputs. Even short circuits across a protection
are detected when the signal is inverted in each sensor (the
protection is then OK), while Vital expects a correctly inver-
ted signal at the right time. In this case, an even number of
sensors are connected to the safety loop which means that
the dynamic signal will be inverted an even number of times
when it is evaluated by Vital. This is determined by the ter-
minal inputs S1 and B1 being connected together. If an odd
number of sensors have been connected, connection of S1 is
not required. As the signal is evaluated by Vital at each pulse,
i.e. more than 200 times per second, faults and short circuits
are detected within a few milliseconds.
How does a dynamic circuit of Vital work?
Light Curtain Focus
Prevents passage with
integrated muting function
Smile Tina
emergency stop
to stop machinery
when there is a hazard
The Eden sensor
monitors that doors
are closed
Emergency stop INCA Tina
To stop the machine in case of
danger
Safety module Vital
monitors the safety sensors
in series according to PL e
ENISO13849-1.