Analog output (ABB AC500 PLC ) scaling

Hi all,

I am new to PLC programming and so far I am able to work with on/off logic quite well. But I am having problem in scaling PLC analog output. I am supposed to write to analog output the value of temperature (0-130 degrees in engineering units). I know that I need to scale engineering units to raw values.

engineering units(0-130) to raw values (0-27648) to analog output (0-10V).

Is the way of scaling analog outputs correct? Do I need to convert from raw values (0-27648) to analog output volts (0-10v) or PLC (ABB AC500) does it automatically?

Looking forward for help.

Regards

I'm not familiar with the PLC that you are using, but any analog output module uses a D/A converter to provide a voltage or current output that corresponds to the numerical value that your program provides to the module for each specific channel. Some PLCs allow for scaling within the hardware configuration so that your program may provide numerical values to the analog output module in Engineering Units, while some require that you provide the raw numbers that are actually used within the module by the D/A converter.

How do I know, whether the PLC I am using requires raw numbers or it can directly scale the engineering units? I mean will that information be provided on the manual of the PLC I am using?

Thank you

muza1988 said:

How do I know, whether the PLC I am using requires raw numbers or it can directly scale the engineering units? I mean will that information be provided on the manual of the PLC I am using?

Thank you

Click to expand...

Yes. The information should certainly be provided by the manufacturer, although the documentation would most likely be found in a manual for the specific analog output module, rather than in the more generic PLC user manual.