Control of directional control valve(festo 4-20mA)

[charl]

Hi.

I hope anyone can help.

I am new fairly new to plc programming.

We have the siemens s7-1200.

I need to control the airflow to steer a small car left and right.

I need some help as how to program this.

I will get a analog value of 0-10V in and need to somehow give a analog 4-20mA out.

I have made a small program that works but not very well it doesnt seem like a lot of proportionality then it gives more pulses than just a variable airflow.

Thanks
Any help is appreciated.

 

[iant]

I assume the air flow is not the direction control.
I have not programmed the 1200 yet.
Can you configure the hardware for the analogue output to 4~20 Ma
This is what is needed - or a difrernt output module

 

[moggie]

I will get a analog value of 0-10V in and need to somehow give a analog 4-20mA out.

Thanks
Any help is appreciated.

Do we assume that 0v input = 4mA output and 10V input = 20mA output?
The S7 1200 has 0-10V AI on the cpu. You will require an AO card for the Output.
6ES7 232-4HB30-0XB0 can be configured for V or mA