HB-37350-810-01-51F-EN SMX Installation manual.docx Page 158 of 234
Version: 50F
5.9 Connection of digital inputs
The SMX comes with 14 (SMX10/11/12) or 12 (SMX31) safe digital inputs. These are suitable
for connecting single or two-channel signals with and without cycling, or without cross-shorting
test.
The connected signals 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, Type1 acc. to IEC 61131-2). The inputs are provided with
internal input filters.
A device internal diagnostic function cyclically tests the correct function of the inputs including
the input filters. A detected fault will set the SMX into an alarm status. At the same time all
outputs of the SMX are rendered passive.
Besides the actual signal inputs, the SMX- module holds two clock inputs P1 and P2 available.
The clock outputs are switching-type 24 VDC outputs.
The clock outputs are solely intended for monitoring the digital inputs (DI1 ... DI14) and cannot
be used for any other function within the application.
The switching frequency is 125 Hz for each output. In the planning stage one must bear in mind
that the outputs may only be loaded with a total current of max. 250 mA.
Furthermore, approved OSSD-outputs can be connected to the inputs I01-I14 without limitation.
In case of single-channel use of the inputs, the achievable safety level must be limited to SIL 2
or PL d, if the safety function is demanded at regular intervals.
A safety related use of the inputs is generally only intended in connection with the pulse
outputs.
If clock outputs are not used, short circuits in the external wiring between different inputs and
against the supply voltage for the SMX must be ruled out by external measures, appropriate
routing of cables in particular.
Each input of the SMX module can be configured individually for the following signal
sources:
Intput is assigned to the cycle T1
Intput is assigned to the cycle T2
Input assigned to continuous voltage DC 24 V
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