schmersal PSC1 - Page 53

Installation manual
HB-37420-810-01-25F-EN PSC1-C-100 Installation manual - V2.2.docx Page 53 of 201
Version: 25F
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.
Only normally closed contacts may be used for safety applications.
PL d according to EN ISO 13849-1 can be achieved when using 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 with use of various 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
S1
A1
Diverse dual-channel input element, without test pulses
Safety instructions: