Siemens SIMATIC S7-400 Reference Manual page 96

Digital modules
4.6 Input characteristic curve for digital inputs
Input characteristic curve for digital inputs
As long as the current flowing into the module remains ≤ 1.5 mA, the module recognizes this
as a "0" signal.
- 30 V
2-wire BERO
Figure 4-1
96
Typ. switching threshold(9.5 V)
I (mA)
E
7
6
BERO
standard
I < 1,5 mA
2
1,5
0,5
0 5 11 13 15
"0"
1
0
Input characteristic curve for digital inputs
Resistance characteristic curve
24
"1"
L+
--> "0" Signal
I < 1,5 mA
M
Reference Manual, Ausgabe 11/2016, A5E00850736-08
I to IEC 61131; type 2
min
I to IEC 61131; type 1
min
30 L+ (V)
PLC input resistance
S7-400 Automation System Module Data