Rockwell Automation 1758-RTU202 DataSite Software User Manual FRN 1.2 - Manual (Page 142)

Publication 1758-UM002D-EN-P - October 2010
142 DataSite Flow Configuration Utility (DS FloConfig)
To obtain the P, T, or DP data from a HART instrument, first you need to use
the HART function in DS FloConfig. You need to know the commands for
reading the engineering values, so that you can store the returned engineering
values into registers. For more information on this, see
Configure HART
Inputs on page 210 .
If the HART instrument cannot provide engineering values directly, you can
do the following calculation to get the values of k and b:
k = (Hi - Lo)/(Hi0 - Lo0)
b = Lo - Lo0*k
Follow these steps to get the values of k and b calculated by DS FloConfig.
1. Click Auto Cal.
The Engineering Conversion dialog box appears.
2. Enter the values of Lo0, Hi0, Lo, and Hi in the dialog box.
3. Click OK.
The values of k and b are calculated by DS FloConfig and are displayed.
HART Address
in 4xxxx USHORT Lo0…Hi0 processed value (Hi-Lo)/(Hi0-Lo0) Lo-Lo0*k
FLOAT
FLOAT Final engineering value 1 0
User Defined
Signal source Address
in 4xxxx FLOAT Simulation data input 1 0
Input Address Data
Type Data k b
IMPORTANT
For the normal signals from AI0~AI5, you should set Lo0
as 10000, Hi0 as 50000.