schmersal PSC1 Series Installation Manual page 73

Installation manual
4.3.4.1.2 Single-channel switching relay or semiconductor output with external switching
amplifier and testing
On the usage of an external switching amplifier, or downstream electromechanical, pneumatic
or hydraulic components, a device for testing the complete chain and a signalling/warning
device on the detection of a fault are required to achieve PL c or higher.
In particular, positively driven auxiliary contacts are required for electromechanical devices, or
valve position signal contacts are required for hydraulic or pneumatic components.
The signalling/warning device must be immediately make clear the hazardous situation to the
operator.
The achievable PL is heavily dependent on the test rate, a maximum of PL d according to EN
13849-1 can be achieved!
X21
Q1_PP
Q2_PN
Q3_PP
Q4_PN
X12
I13
I14
T1
T2
X13
NC
NC
Y1
Y2
L +
L -
Figure: Single-channel switching relay output with testing
Safety instructions:

Only recommended to a limited extent for safety applications! On this topic see also the
information in EN 13849-1 on usage and the fault exclusions necessary.

For PL c or higher a test rate > 100 * demand rate is required

For PL c and higher a signalling/warning device is required that immediately makes
clear the hazardous situation to the operator
HB-37350-810-01-38F-DE PSC1-C-10 Installation manual V1.1.docx
Version: 38F
Page 73 of 177