Hi

 I have two pressure sensors 4-20mA. One is 400mbar and other 250mbar connected on logo 8 analog module

I want to scale them so I can measure ma for both sensors on logo screen.

Since this signal is treated first as 0-20ma both sensors will have same scale settings (analog amplifier block) Range   minimum=0 maximum 2000    and parameter Gain=2  Offset=0. Am I correct on this?

When scaling first sensor 0-400mbar ,settings are minimum=0 maximum 4000    and parameter Gain=5  Offset=-1000 I think this is correct.

What parameters to use for 0-250 mbar sensor? Are following parameters correct to use

minimum=400 maximum 2000    and parameter Gain=2  Offset=0  ?

Or minimum=1 maximum 2505    and parameter Gain=3.13  Offset=-625 as suggested?

And why please.

Thanks in advance

Chris

You make life difficult for yourself, maybe because you are not reading the online help of Logosoft.

If you have a 4..20mA sensor, then first select 4..20mA in the analog amplifier, then enter the range on left side, not the parameter on right side, they are calculated from Logosoft.

If you have a range 0..400mBar, use 0..400 for 0 decimals or 0..4000 for 1 decimals.

If you have a range from 0..250mBar, use 0..250 for 0 decimals or 0..2500 for 1 decimals.

If you have a range from 4..20mA for display, use 4..20 for 0 decimals, 40..200 for 1 decimals or 400..2000 for 2 decimals.

It's everytime the same method. When you get a red message, then gain and offset of the amplifier cannot be calculated exactly or gain is outside of possible range, because gain is limited to 2 decimals and between -10.00 and +10.00. Normally you can ignore this message in case of limited 2 decimals with a width range e.g. 0..2500. Alternatively the value can also determined with 2 amplifiers or arithmetic block.

See also the attached picture, Scorp

I have found a little mistake in my program for displaying sensor 2 mA, it's not block 19 but block 17 to show the right value. See attachment for corrected version.

Regards, Scorp