schmersal PSC1 - Connection of the Digital Inputs

Installation manual
HB-37420-810-01-25F-EN PSC1-C-100 Installation manual - V2.2.docx Page 125 of 201
Version: 25F
5.10 Connection of the digital inputs
• The PSC1 has 14 (PSC1-C-100 (-FBx) and PSC1-E-37) or 12 (PSC1-E-21-SDM1,
PSC1-E-22-SDM1-2, PSC1-E-23-SDM2, PSC1-E-24-SDM2-2, PSC1-E-131/133) safe
digital inputs. These are suitable for the connection of single or dual-channel signals with
and without test pulses, or without cross-circuit testing.
• The signals connected must have a "high" level of DC 24 V (DC +15 V..+ DC 30 V) and
a "low" level of (DC -3 V... DC +5 V, type 1 according to IEC 61131-2). The inputs are
equipped internally with input filters.
• The device-internal diagnostic function cyclically checks the correct function of the inputs
including the input filter. The detection of a fault places the PSC1 in the alarm state. At
the same time all outputs on the PSC1 are rendered passive.
• Along with the actual signal inputs, the PSC1 module provides two pulse outputs T0 and
T1. The pulse outputs are switching 24 VDC outputs.
• The pulse outputs are only intended to be used for monitoring the digital inputs (I0 ...
I13) and cannot be used for any other functions in the application.
• The switching frequency is 125 Hz for each pulse output. During planning it is to be
noted that the pulse outputs are allowed to be loaded with a maximum total current of
250 mA.
• In addition, approved OSSD outputs can be connected to the inputs I00…I13 without
restriction
• On the single-channel usage of the inputs, the safety level that can be achieved is
limited to SIL 2 or PL d, if there is no demand for the safety function at regular intervals.
• In principle, safety-related usage of the inputs is only intended in conjunction with the
pulse outputs.
• If the pulse outputs are not used, a short-circuit in the external wiring between different
inputs and the supply voltage for the PSC1 must be excluded by means of suitable
external measures, in particular suitable cable routing.
• Each input on the PSC1 module can be configured individually for the following signal
sources:
o Input is assigned pulse T0
o Input is assigned pulse T1
o Input is assigned DC 24 V continuous voltage