Siemens SIMATIC S7-400H Manual page 157

AI 16x16bit
• For voltage measurements: The "wire break" diagnostic function may not be
enabled in HW Config when the module is operated with measurement
transducers or thermocouples
• You can use a 50 Ohm or 250 Ohm shunt resistor for voltage measurements:
Current measurement range
Input range to be configured
Measurement range selector position
Resolution
S7 number format
Measurement error caused by circuit
– 2 parallel inputs
– 1 input
"wire break" diagnosis
Load resistance for 4-wire measurement
transducer
Input voltage for 2-wire measurement
transducer
Automation System S7-400H Fault-tolerant Systems
A5E00068197-07
6ES7 431-7QH00-0AB0
Resistor
Using I/O on the S7-400H
50 OHM
+/–20 mA +/–20 mA
+/–5 V +/–5 V
A A
15 bits + sign bits + sign
X
–
–
X
50 Ohm 250 Ohm
> 1.2 V >6 V
250 Ohm *)
4...20 mA
1...5 V
15 bits
–
–
x
7-27