Hello Everyone,

I'm trying to do the following in my program, if you could help me out I'd appreciate it!

I have a position sensor that is providing a range of operation from 7 mA (0%) to 17 mA (100%), the idea is to use the LOGO module to normalize this these values in an analog output of 4 mA (0 %) and 20 mA (100%). 

I tried with the block analog amplifier with a gain of 1 and with an offset of -200, with it, I was able to reduce the 7mA to 4mA on the output but also the 17mA decrease to 14mA. 

The input sensor has a configuration of 4…20mA, same as the output.

Thank you in advance!

Filipe

The Sensor range is 4 to 20 mA, the reason for this deviation is due to Hydraulic limitations on the valve.  Although I receive 7mA we can visualize that the valve is fully close and when we receive the 17mA is fully open.

Unfortunately, it's not possible to change the position of the sensor.

Could you please share the configuration for the "Mathematical Operation" Block? I'm Unable to replicate the same as you .

This is the program that o tried to do, but I can't replicate the same mathematical operation as in your file.

I have already configured the input/output to the correct ones on for the logo

First thanks for the correction from the previous configurations. 

I checked the program through simulation (since I can only access the job site on Monday) and it seems like the 7mA to 4 mA is working, but the 18mA to 20 mA is not reaching this value.

More data from the real situation, Yesterday with no Amplification I reached these results with the sensor out to at least know what is the value on LOGO for the 4mA and 20 mA situation :

-4mA

AI3 i have 403 and on AQ2 i have 403

-18 mA

Ai3 i have 902 and on AQ2 i have 902

Using your program  through simulation : 

- 4mA

 On AI03 i have 611 and on the AQ2 i have 402 ( which is working as it should)

- 18mA

On AI03 i have 905 and on the AQ2 i have 854 ( which is below the desired value in reality is should be around 920)

Unfortunately, it seems like it's not working.

Using your program :

When I have a Current input of 7mA I should have an output unit 403 but in reality I have 16

When I have a Current input of 17 mA I have an out of 1026 which is correct. 

As per your program the output is working between 0 mA to 20mA, but i need to change the range from 4mA to 20mA.

I understand that it's a bit tricky and not sure if it's possible with the LOGO Module, because in reality I need to “push” down the 7mA to 4mA and then raise the 17mA to 20mA

I sent you a PM, just in case.

Hello ixo65,

The last version that you provided worked as it should (better in real life than in simulation), only a small adjustment on the off set and gain was necessary, but it's now working perfectly.

Thank you for your support.