kHz signal on digital input

[arnoldzw 1]

Hi all,

 

I have an question for something i haven’t seen before, hope someone can help me.   

There is an FX2N plc with an level transmitter connected to an digital input. 

The output signal of the leveltransmitter is an kHz frequency. 

Level = 0-10 meter = 1-2 kHz

 

PLC needs new software, cliënt wants to keep this sensor. change sensor for 4-20ma is not desirable by cliënt, also there is no analog input available. 

 

Is there anybody who has seen this before? How can this sort of input been scaled to an level value inside plc? 

Something with counter/scale blocks?

[Ron_S 61]

The first few inputs can be used as high speed counter inputs.

They are tied to specific high speed counters.

Sampling of the frequency and a bit of scaling maths can give you the level

[Inntele 60]

Look at the SPD instruction then scale its result to get a level value.