User manual

MVI56-HART ♦ ControlLogix Platform Configuring the MVI56-HART Module
HART Multi-drop Master Communication Module User Manual
ProSoft Technology, Inc. Page 47 of 171
October 13, 2011
2.3.2 Example of HART Command Function 34
The following example shows how to configure a command function 34 (WRITE
DAMPING VALUE) to write a damping values (seconds) to the HART slave device.
According to the HART specification, this command will write one floating point variables:
Word High Byte Low Byte
0 Floating Point Damping Value (Sec)
1
The HART device should also return the floating point value after it processes the
request:
Word High Byte Low Byte
0 Floating Point Damping Value (Sec)
1
The HART device also returns an integer status data:
Word High Byte Low Byte
1 STATUS WORD
This command will return the following number of words:
Parameter Data Type Direction Number of
Words
Database Address
(this example)
Damping Value Floating Point Written from MVI to slave 2 (4 bytes) 400 (word address)
or 800 (byte
address)
Damping Value Floating Point Read from slave to MVI 2 240 (word address)
Status Word Integer Read from slave to MVI 1 290 (word address)
The user can configure the command parameters as described in the following table.
Index Parameter Value Observation
1 Enable 1 The command is sent continuously
2 Float DB
Address
300 The damping value response will be copied to the
internal database starting at word-address 300
(occupies addresses 300 to 301)
3 Poll Interval 0 The command is sent without any delay
4 Word Count 2 The command returns 10 words of floating point
data
5 Swap Code 3 The bytes in each returned floating point word are
swapped
6 Short Address 0 This command is sent to the Hart slave device using
short address 0
7 Function Code 34 The command function 4 (WRITE DAMPING
VALUE) is used in this example
8 Int. DB Address 320 The integer data will copied to the database word-
address 320
9 Word Count 1 The command returns 1 word of integer data
10 Swap Code 3 The bytes in each returned integer data will be
swapped
11 Use Long 1 This command executes using Long Address