Hello all,

I am having a real nightmare trying to scale an AQ on a Logo.  I use the 1200 range regularly but for this project i thought I’d use a logo due to the simplicity….  Or so I thought!

Background

I have a logo collecting modbus data from a power meter and I need to scale the kw value from the power meter to a 0-10 or 4-20mA signal

Two issues I have:

The power meter data is float data type made up from two 16bit word registers, how can I read this value in my logo?  Expected value is -2000.0 to 2000.0 kW

Once I have this value how do I scale the output as below

0-10V

-2000.0 – 2000.0

0r

4-20mA

-2000.0 – 2000.0

In the 1200 it’s a relatively easy task but in the logo I’m getting completely lost or missing something!  Any help appreciated!

Great!

Any tips appreciated!  i'm seriously looking to ditch the LOGO and bring a 1211C in tomorrow!

Cheers M

Of course but this is nuts!

How do you get a gain of 0.25 and offset off 500 to equal a scale of -2000 - 2000?

Cheers M

Thank you for the info.

The project here is more complex than I anticipated, i have to do some additional math and write the data to a different slave address also.

I'll bring a 1211 with me tomorrow and save this logo for some of the logic panels we supply.

Cheers M

HI,

Yeah i'm sure it will do it but I have limited time on this one so i'll stick with what i know on the 1200.

the Logo is a great product but i just couldnt get my head around that scalling yesterday from modbus to AQ.

I'll use it on another project when I have more time :-) 

Thanks for teh response.

Cheers M