I am working on a s7400-h plc with some ET200M modules and expansion I/O modules.

I am checking the loaded program.

I noticed although 2- wire transmitter is connected to AI module (6ES7331-7NF00-0AB0), the 2 wire configuration can not be chosen for this module.

why there is no 2 wire option in configuration. I have attached the configuration section for AI module only 

deactivate voltage and 4 wire current can be selected (it should be mentioned that the transmitters are connected to the AI modules via MTA)

Hello,

Perhaps the following points might help:

• 1-6ES7331-7NF00-0AB0

SIMATIC S7-300, Analog input SM 331, isolated, 8 AI; +/-5/10V, 1-5 V, +/-20 mA, 0/4 to 20 mA, 16 bit (55ms), Single rooting (50 V COM.), 1x 40-pole

• 2 wires transmitter is powered by the loop current.
• 4 wires transmitter is powered by an external supply.