
HART Communications
4.1 Universal HART Commands
F US Clamp-on Communications Protocol Manual
Hardware Installation Manual, 11/2015, A5E34981613-AC
39
Table 4- 4
Command 2 - Read Loop Current and Percent of Range
Description
Byte
Format
Comments/Value
Primary Variable Loop Current
0-3
Float
<units in milli-amperes>
Primary Variable Percent of Range
4-7
Float
<range set in CMD 35>
Table 4- 5
Command 3 - Read Dynamic Variable and Loop Current
Description
Byte
Format
Comments/Value
Primary Variable Loop Current
0-3
Float
<units in milli-amperes>
Primary Variable Units
4
Enum
< write units CMD 44 or 53>
Primary Variable
5-8
Float
<write PV variable CMD 51>
Secondary Variable Units
9
Enum
<write SV Units CMD 53>
Secondary Variable
10-13
Float
<write SV variable CMD 51>
Tertiary Variable Units
14
Enum
<write TV Units CMD 53>
Tertiary Variable
15-18
Float
<write TV variable CMD 51>
Quaternary Variable Units
19
Enum
<write QV Units CMD 53>
Quaternary Variable
20-23
Enum
<write QV Variable CMD 51>
Table 4- 6
Command 6 - Writing Polling Address
Description
Byte
Format
Comments/Value
Polling Address of Device
0
U-8
Loop Current Mode
1
Enum
0-disabled 1-enabled
Table 4- 7
Command 7 - Read Loop Configuration
Description
Byte
Format
Comments/Value
Polling Address of Device
0
U-8
Loop Current Mode
1
Enum
0-disabled 1-enabled
Table 4- 8
Command 8 - Read Dynamic Variable Classifications
Description
Byte
Format
Comments/Value
Primary Variable Classification
0
Enum
0-not classified
Secondary Variable Classification
1
Enum
0-not classified
Tertiary Variable Classification
2
Enum
0-not classified
Quaternary Variable Classification
3
Enum
0-not classified