Siemens SIMATIC ET 200AL System Manual page 1415

What you should know about analog technology
2.20 Burden with 2-wire transducers
Example 1: Connecting a transducer to the electrical circuit
In accordance with the technical data of the 2-wire transducer used, it requires a supply
voltage (U
transducer used (R
With a supply voltage of at least 8.5 V, the transducer has a resistance of 425 Ω. The
resistance is less than 820 Ω. You can therefore connect the transducer to the analog input
module (AI) without exceeding the maximum burden.
①
U
V
I+
U
min
Figure 2-27
58
) of at least 8.5 V. Using Ohm's Law, you can calculate the resistance of the
min
) for a current of 20 mA.
2DMU
2-wire transducers
Terminal for feed voltage at the channel
Terminal for current input
Voltage drop at 2-wire transducer
Connecting a transducer to the electrical circuit
Analog value processing
Function Manual, 06/2014, A5E03461439-AC