scaling analog input in Cscape touchscreen

[nosajnil]

I am trying to display an analog input on the screen, but it is not scaling properly.
The pressure sensor is a Setra_Model_264. that measure 0 to 0.1 " of water column. then output 0 to 5 Voltes.
In the debug mode, the number seems to scale correctly to -0.01045.
But the display on the screen is showing -17825 (it fluctuate from -24326 all the way up to 31038).
You may see the register I used in the attachment.

 

[Gene Bond]

You are scaling to a Real, but displaying a signed decimal with no decimal places...

 

[nosajnil]

Real number can also be negative with decimals right? (is Real number the same definition in PLC vs math world? )

 

[g.mccormick]

Real are floating point. So the 32 bits make up value and matissa.

 

[Gene Bond]

Several Options. I am not certain which is correct for your data, but you don't show decimals in the format, and you did not select Real... (see snips)

 

[nosajnil]

Thank you everyone. I changed the analog input to 16 bit, the rest to be 32 bit for real numbers. display as real with decimal and works!

 

[nosajnil]

So it was working fine displaying 32 bit on a number display.
I wanted to show on a circular gauge which takes 16 bit as input.
I convert the number using real to int. But now both the 32 bit and 16 bit number goes to zero. why is that?

 

[labeledas]

hard to tell but looks like pressure is 8.06xxx e-4 so converting to int 0.0000806xxx out to zero

does your gauge take 16bit int

 

[labeledas]

sorry misread your post it's possible the 32 bit takes up two memory slots and you are overwriting part of it with you real to INT function

%R01011 may be part of your 32 bit %R01010

Move you real to INT to %R01012


from manual

32-bit values (DWORD, DINT, UDINT) occupy 32 consecutive bits of data, or two (2 consecutive 16-bit
registers. For example, if a DINT is defined at Register %R43, the 32-bit value is contained in %R43 and
%R44.

 

[nosajnil]

Thanks, that did the trick! I remember professor warn us about similar things in C programming language class. I never bother about it assuming there is unlimited memory.