Scaling analog inputs

[Guest Ian Spiteri]

Hey guys!! First of all I would like to thank you for the feedback you gave me regarding subroutines. Now that I know how subs work, I am trying to use the analog inputs. I tried using the "scale inputs" commmand. It is quite straight forward except that I still find it difficuilt to obtain a value to be saved in a register e.g. N7:0. For example: If I apply a 6V d.c. signal I would like to obtain a value such as 600 to be saved into an integer variable. I tried reading the help but still I didn't understand those formulae. Any help???

[mgvol 0]

I don't know what type of processor you are using, so this sugestion may not apply. In RSLogix, in the instruction toolbar, scroll over to the right and near the end, see if you have an advanced math tab. If so, see if you have the SCP (scale-with-parameters) instruction available. If you do, use this instruction per the example:

[mgvol 0]

Oops, the attachment didn't make it. Document1.pdf

[mgvol 0]

The raw values you put into the scaling instruction will depend on how you have configured the analog module(s). I see from your previous post that you are using ML1500 PLC, so your analog has to be a 1769 series. If you are using ML1500, the SCP instruction shoulod be available to you. Attached is the data format matrix for a 1769-IF4 analog input module. If this is not the module you are using, post here and I will get you a .pdf of the user's manual for the appropriate module. scaling.pdf.zip