Instruction Manual
D103785X012
Configuration
June 2017
38
HART Variable Assignments
Instrument variables can be reported via four different HART variable assignments. The Primary Variable is always
configured as Analog Input. However, the remaining three variables have additional options as listed below.
Primary Variable (PV)
Analog Input
Secondary Variable (SV)
Travel, Travel Setpoint, Pressure A, Pressure B, Pressure AB, Supply Pressure,
Drive Signal, or Analog Input; default value is Travel Setpoint
Tertiary Variable (TV)
Travel, Travel Setpoint, Pressure A, Pressure B, Pressure AB, Supply Pressure,
Drive Signal, or Analog Input; default value is Pressure A.
Quaternary Variable (QV)
Travel, Travel Setpoint, Pressure A, Pressure B, Pressure AB, Supply Pressure,
Drive Signal, or Analog Input; default value is Travel.
Transmitter Output
This configures the relationship between the valve travel and the position transmitter output signal. There are two
choices; 4mA = Valve Closed or 4mA = Valve Open.
Burst Mode
Burst mode provides continuous communication from the digital valve controller. Burst mode applies only to the
transmission of burst mode data (HART Variable Assignments) and does not affect the way other data is accessed.
Burst mode is only available in devices configured as HART Universal Revision 5.
D
Burst Enable—
Turns on or off the burst mode.
D
Burst Command—
Defines which HART command is configured for burst reporting. There are three options to
choose from. When using a TriLoop, select the third option.
- Analog Input (Command 1)
- Loop Current / Travel (Command 2)
- Loop Current / PV / SV / TV / QV (Command 3)
Note
Access to information in the instrument is normally obtained through the poll/response of HART communication. The Field
Communicator or the control system may request any of the information that is normally available, even while the instrument is in
burst mode. Between each burst mode transmission sent by the instrument, a short pause allows the Field Communicator or
control system to initiate a request. The instrument receives the request, processes the response message, and then continues
“bursting” the burst mode data.
Burst mode will be disabled by ValveLink software during diagnostics tests such as Valve Signature.
Note
If the instrument is configured to operate in pressure control mode, or detects an invalid travel sensor reading, the Travel variable
will report pressure in percent of bench set range.