Siemens SIMATIC S7-400H System Manual page 144

Using I/Os in S7-400H
10.5 Connecting redundant I/Os
Additional conditions for specific modules
AI 8x12-bit 6ES7 331–7K..02–0AB0
● Use a 50 ohm or 250 ohm resistance to convert the current to a voltage:
Resistance
Current measuring range
Input range to be set
Measuring range cube position
Resolution
S7 number format
Circuit-specific measuring error
- 2 parallel inputs
- 1 input
"Wire break" diagnostics
Load for 4-wire measuring transducers
Input voltage for 2-wire measuring
transducers
*) The AI 8x12-bit outputs diagnostic interrupt and measured value "7FFF" in the event of wire break.
The listed measuring error results solely from the interconnection of one or two voltage
inputs with a shunt resistor. Allowance has not been made here for the error tolerance, or for
the basic/operational error limits of the modules.
The measuring error for one or two inputs shows the difference in the measurement result
depending on whether two inputs or, in case of error, only one input acquires the current of
the measuring transducer.
AI 8x16-bit 6ES7 331–7NF00–0AB0
● Use a 250 ohm resistor to convert the current to a voltage:
Resistance
Current measuring range
Input range to be set
Resolution
S7 number format
Circuit-specific Measuring error
- 2 parallel inputs
- 1 input
"Wire break" diagnostics
Load for 4-wire measuring transducers
Input voltage for 2-wire measuring transducers
*) It may be possible to use the freely connectable internal 250 ohm resistors of the module
AI 16x16-bit 6ES7 431–7QH00–0AB0
144
50 ohms 250 ohms
+/-20 mA +/-20 mA *)
+/-1 V +/-5 V
"A" "B"
12-bit+sign 12-bit+sign
x x
- 0.5 %
- 0.25 %
- -
50 ohms 250 ohms
> 1.2 V > 6 V
250 ohms *)
+/-20 mA
+/-5 V
15-bit+sign
x
-
-
-
250 ohms
> 6 V
System Manual, 09/2007, A5E00267695-03
4...20 mA
1...5 V
12-bit
x *)
4...20 mA
1...5 V
15-bit
x
S7-400H