Rockwell Automation PLC-5 Fieldbus Solutions for Integrated Architecture User Manual - Manual (Page 286)

Publication 1757-UM006A-EN-P May 2002
F-38 1788-CN2FF Installation Example
process swaps the sequence of the data floating point which is the
process variable.
To get the analog value into floating point format so you can use the
data, you need to swap the sequence of the words, and then copy the
32 bit value to a Floating Point data table. When you do the copy,
specify a length of 1.
When you are finished, you should be able to use the Monitor
Function in the Fieldbus Configuration software to monitor the data
coming from a Fieldbus device, and using a second window on the
PC monitor, see the same value in the Floating Point Data Table in the
controller. If you happen to have Fieldbus sensors that show the value
that they are transmitting, all three readings should be the same.
If you are using a PLX system
The Offset Values must be set on the IN function blocks, which you
drag to your Control Module from the Library. If you are receiving
data from a Discrete IN, DI, function block, you will drag and set the
offset in an IN_D function block.
If you are using a CLX processor
Tech Support at 440-646-5800 can provide a CLX program that
includes a structure that spreads the FF data so it is understandable.
You can obtain the ControlLogix Example Code by doing the
following:
1. Visit us at www.ab.com
2. Click on Product Support.
3. Click on Knowbase.
4. Search on Knowbase document number: A5754787 .
5. Double click the file and download to you PC.
With the CLX, there are two pad bytes before the real data from the
CN2FF starts to appear. Therefore, the CLX program from Tech