Looking for a GX Works guru

[Electric3906]

Hi Guys

I'm trying to scale an Analog input. The manual talks about comparing the analog to a data table to result as another device. Function 259 or SCL is pretty straight forward, except the data table part.

The examples and explanations in the manual and help files are not clear and I cannot find where to access, how to build, enter or modify a data table.

There must be a GX works guru out there with scaling experience who can point out what I am missing?

Cheers PN

 

[doomsword]

Which PLC and is it GW2 or GW3?
Anyways all manual are here: http://www.mitsubishielectric.com/app/fa/download/search.do?kisyu=/plcr&mode=manual


I don't understand what are you trying to do exactly...

 

[Electric3906]

I have an FK3U PLC, a clone of a Mitsubishi FX3U. Using GX Works 2 to program.
I'm building a battery charger so there are analog inputs for volts and amps setpoints, volts and amps outputs. There are multiple tappings on the transformer and other features that the PLC is controlling.

The PLC analog inputs are configured for 0-10V, this ends up as 0-4000 counts in the PLC. But the volts setpoint potentiometer ended up as a maximum of 7.2V so it's maximum count is 2810, not 4000. The maximum output voltage is measured at 95V DC. After configuring the signal and measuring by the PLC, it ends up at 2430 counts in the PLC.

Currently, when I compare Volts setpoint to the output, the scales do not match.

I want to scale the voltage setpoint to see 2810 counts and give a 4000 count. The output voltage when at 2430 counts needs to be scaled to give 4000 counts. This way, 50% = 50% in both cases: 2000 counts. This can then be used in the rest of the logic to drive deadbands, comparisons etc in the PLC which drives the voltage control and selects the appropriate transformer tapping and all the other things it is wired up to do.
The current control system is a similar problem, but also needs to control the output voltage because Ohm's Law.

 

[cottagewood]

You could just multiply the input by 1423 which will put the answer in to a double integer, then divide by 1000.
Or you could convert the input to REAL and multiply it by 1.423