Experimental Physics and
Industrial Control System

"Mark Rivers" <[email protected]> · Mon, 13 Nov 2006 20:22:06 -0600

Device support must have a "convert" routine that does a calculation like the following to compute .ESLO and .EOFF

        precord->eslo = (eguf - egul)/(deviceHigh - deviceLow);
        precord->eoff = (deviceHigh*egul - deviceLow*eguf)/
                        (deviceHigh - deviceLow);

Mark

________________________________

From: David Dudley [mailto:[email protected]]
Sent: Mon 11/13/2006 8:07 PM
To: [email protected]
Subject: Scaling Database entries

OK guys,

My modbus driver is starting to work, and now I'm linking up with some of the PLC's in the plant.  Now, I've started working on building the database for the first site.

Here's my question:

I've got some AI signals that come from one of the PLCs.  Raw values on some are scaled 0-32000, while others are scaled 800-32000, and others have raw values from -32768-32767.  I see the definitions for the EGUL and EGUF values, but how do I set the RAW input ranges?  Also, I've got some flow meter values that have to be scaled from linear to square root values..

David Dudley
City of Corpus Christi

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System