Software User Manual FRN 1.2 Owner manual

Publication 1758-UM002D-EN-P - October 2010

58 DataSite Configuration Settings Utility (DS Settings)

Here is an example of a HART configuration list:

Understand HART Commands

Some of the variables read from HART equipment are 32-bit floating-point

values. Every floating-point value is stored in two continuous data registers.

The higher 16 bits of this value will be stored in the register with a higher

address and the lower 16 bits of this value will be stored in the register with a

lower address. For example, if a 32-bit double precision IEEE floating point

number, such as 1234.5678 is to be stored, two registers, such as register 40108

and register 40109 can be combined to store the number. In hexadecimal,

1234.5678 is 449A 552B. The DataSite controller will store 449A in register

40109 and 522B in register 40108.

Registers Used in HART Commands

The following table lists the number of registers used in each HART command

for the four register types, namely Send, Return, Unit and HART state.

Number of registers used in each HART command

Command Description Number of registers

Send register Return register Unit register HART state

0 Read Unique Identifier 0 10 0 2

1 Read Primary Variable 0212

2 Read P. V. Current And Percent Of Range 0402

3 Read Dynamic Variable And P. V. Current 0 10 4 2

15 Read Transmitter Variables 0 10 0 2

33 Read Primary Variable Output Information 4 12 4 2

35 Write Primary Variable Range Values 9002

38 Reset Configuration Changed Flag 0002

40 Enter/Exit Fixed Primary Variable Current

Mode

4002

44Write Primary Variable Units 1002