ab scaling rslogix 5000

Good day everyone,

I am a little confuse about the analog input of ab and its setup and configuration.. why do we need to config the hardware input analog module and then create a program to scale the input.

how do i interpret the engineering unit at the hardware config.

the default number is from 3277 to 16383.. what are the other numbers?

TY,
WArm Regards,

The 1734 and 1769 Series of I/O don't do the scaling in the module like the 1756 (Controllogix) series does. So you have to set up the D/A counts in the Hardware Configuration. Then do the scaling of that D/A Value in the program to get the actual "Real World" value.

You can use other numbers in the scaling as long as it is within the range of the module. You will have to look at the manual for the individual module to make sure you are within the range it uses.

Most of the time I use 4000 on the low end and 20000 on the high end to emulate the 4-20mA signal. It helps me to know exactly what the signal is by just looking at the counts. I.E. 8500 = 8.5 mA

Could you use the low and high engineering values to be a "defacto" scaling? I guess you could but what you would sacrifice is resolution. You could set your card to 0-100 counts to represent 0-100psi. The problem will be is every count is equal to 1 psi. That might be ok for your application but other application that resolution will not work. even if you did 0-1000 you would then have to add a line in the program to divide it by 10 and get it back to your 0-100 range so you really didn't save any time.

Hope this helps you out.