Arduino Uno, converting signals

Other Hardware Sensors
1

Hello friends, this is my first post here, if i'm doing something wrong, forgive me!

Now let's get started, in my CBT group is necessary to make the communication of an Arduino Uno board that receives 0-5V, with various tools such as a level sensor, flow, one PT 100 thermocouple. These tools belong to a FESTO process control plant aquiring data and transmiting the signals to the Arduino.

In this case, we need to create communication with the level sensor which transmits an analog 4-20 mA signal; The flow sensor, which transmits a square wave with frequency change 5-12V and communication with the PT100.

The question is:

Knowing that the Arduino receives 0-5V, how is it possible to do the conversion and communication of these signals?

2

Well, let's see,
If V = I x R , => R =V/I

and I = 20 mA (0.020 A),
and V = 5 V,

then R =V/I = 5/ 0.020 = 250 ohms (across the 20 mA current line to ground.

As far as everything else you mentioned, when you post the link to datasheets then maybe we can discuss that.

3

Here is a typical interface for 4-20Ma. I think it was for an ultrasonic flow meter. If your flow meter is a Hall effect device, there is a project that can be downloaded from Jaycar or Freetronics. PT100s are typically used with an op-amp.

rtdmodule.png
rtdmodule.png3334×2305 49.3 KB

4-20 ma.png

4

I see the RTD inputs but where is the 20 mA current loop ? (is that what the RTD is connected across ?)

5

Hi Nick, I interested in your PT100 schematic diagram.. That is for 3 wire or 4 wire PT100??

Nick_Pyner:
Here is a typical interface for 4-20Ma. I think it was for an ultrasonic flow meter. If your flow meter is a Hall effect device, there is a project that can be downloaded from Jaycar or Freetronics. PT100s are typically used with an op-amp.