Installation manual
PSC1-C-10 Installation manual V2.6
Page 47 of 173
Version: 57E
4.2.1.4.3
Dual-channel sensor without time monitoring and without cross-circuit testing
Faults are detected as a minimum on demand. The DC is medium and can be changed to the high
category by using cyclic tests (start tests, operative/organisational tests) depending on the test
frequency.
For this purpose only normally closed contacts are to be used for safety applications.
PL d according to EN ISO 13849-1 can be achieved on the usage of sensors / switching elements with
fault exclusion for the failure of the switching contacts to open. This exclusion is allowed on the usage
of positively opening switches with correct positive actuation. It is also allowed to use sensors with
self-monitoring output contacts.
PL e according to EN ISO 13849-1 can be achieved on the usage of diverse sensors / input elements
with an adequately high MTTF
D
in conjunction with plausibility monitoring of the timing and an
adequately high change in switching state = dynamic testing.
I00
I01
I02
I03
T0
T1
X14
.
.
.
L+
L-
X12
Homogeneous dual-channel sensor without test pulses, with positive opening
I00
I01
I02
I03
T0
T1
X14
.
.
.
L+
L-
X12
S
1
A
1
Diverse dual-channel input element, without test pulses
