Varec 4120 Installation and operation manual - page 21
IOM006GVAE1103
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4120
Section 5 - HART Protocol Implementation
This section describes the HART implementation details for the METT. HART devices can
return up to four dynamic variables with a single read. The METT has many more
variables. HART devices have a mechanism that allows internal transmitter variables to
be mapped to dynamic variables. Dynamic variables can be read via Commands 1 and
3 and are sometimes referred to as process variables (PVs). Command 33 allows reading
of the transmitter variables directly by specifying their ID.
Transmitter Variables
The METT has the following transmitter variables available.
Standard HART
Commands
The METT supports the following standard HART commands. Refer to the HART
documentation for details on request and reply data.
Transmitter Variable ID
Description
1 Average
Temperature
2
Level
10 - 21
Temperature 1 - Temperature 12 (1 is bottom, 12 is top)
50 - 61
Resistance 1 - Resistance 12 (1 is bottom, 12 is top)
HART Command
Description
1
Read primary variable
3
Read all dynamic variables
6
Write poll address
12
Read message
13
Read tag, descriptor, date
14
Read primary variable sensor information
15
Read primary variable output information
16
Read final assembly number
17
Write message
18
Write tag, descriptor, date
19
Write final assembly
33
Read transmitter variables
34
Write primary variable damping
38
Reset configuration changed flat
39
EEPROM Control
44
Write primary variable units
48
Read additional Transmitter Status
50
Read dynamic variable assignments
51
Assign transmitter variables to dynamic variables
53
Write transmitter variable units
54
Read transmitter variable information
55
Write transmitter variable damping
59
Write number of response preambles
122
Write device ID number
253
ASCII exchange command