Crimson 3 MB Read Dbl Precision Float

Hi everyone,
I am using a Red Lion G07 to read a value out of a batch controller via Modbus TCP/IP. The value I want to read is listed as a Double Precision Float and has 4 MB registers that need to be read. The problem is I don't see a Double Precision Float as a choice in the "Treat As" part of the tag set up. I just get Signed Integer and Floating Point.

Any ideas on how I can get this value into the HMI?

Thanks for the help.

I believe those will be 64 bit floats. You might be in for a bit of work to get those values to display properly on the HMI, if at all. Before you take on the task of writing a program to convert them, you may want to find out if you can read them in using some other format with the Crimson Modbus driver.

If it is possible to pull them in as INTs or Long INTs, then you may be able to write a function to pick apart the exponent and fraction and sign bit and create something that looks like a 64 bit float, or just a 32 bit float that represent the value as close as possible.

The way I do this with a Krohne meter is to pull (2) consecutive long (32-bit ints) and put them into an array, and then use the R64TOREAL() function in a program.

E.g.
400001.LONG -> Array[0]
400003.LONG -> Array[1]

then

mynumber = R64TOREAL(Array[0]);

Not long after I posted I realized that I could move the item I need into one of the 100 user floating point registers that are in the Batch Controller and it should do the conversion for me from double precision to single precision. I can then just read from the user float area.

If I can't make that work I will give Epy's solution a try.
Thanks for the help guys.

Epy said:

The way I do this with a Krohne meter is to pull (2) consecutive long (32-bit ints) and put them into an array, and then use the R64TOREAL() function in a program....

Click to expand...

Good to know that Red Lion has taken care of the hard part for us. I have not had to deal with 64 bit real numbers yet.

Yup! I was so happy after talking to the support guy. It was a lot bigger deal to handle this in a MicroLogix.