Prosoft-technology MVI69-HART Manual de usuario descargar pdf (Pagina 42)

Module Configuration MVI69-HART ♦ CompactLogix Platform

User Manual HART Multi-drop Master Communication Module

Page 42 of 169 ProSoft Technology, Inc.

March 29, 2012

2.3 Hart Command Examples

This section describes two examples that shows how to configure HART

commands. The first example shows a read command (function code 3 - READ

DYNAMIC VARIABLES) and the second example shows a write command

(function 34 - WRITE DAMPING VALUE).

2.3.1 Example of HART Command Function 3

The following example shows how to configure a command function 3 (READ

DYNAMIC VARIABLES) to read the process variables from the HART slave

device. According to the HART specification, this command will return four

floating-point variables:

Word High Byte Low Byte

0 Current (mA)

2 Primary Variable

4 Second Variable

6 Third Variable

8 Fourth Variable

The command also returns the following integer data:

Word High Byte Low Byte

0 Status Word

1 Primary Variable Units Code Second Variable Units Code

2 Third Variable Units Code Fourth Variable Units Code

So, this command will return the following number of words:

Parameter Data Type Direction Number of

Words

Database

Address

(this example)

Variable Results Floating Point Read from slave to MVI 10 240 (word address)

Status/Unit Codes Integer Read from slave to MVI 3 290 (word address)

1 2 ... 37 38 39 40 41 42 43 44 45 46 47 ... 168 169

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Prosoft-technology MVI69-HART Manual de usuario Pagina 42