Primary value (pv), Secondary value, Third value (tv) – Rockwell Automation 1756-OF8H ControlLogix HART Analog I/O Modules User Manual
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Rockwell Automation Publication 1756-UM533C-EN-P - February 2011
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Glossary
owner-controller
The controller that creates and stores the primary configuration and
communication connection to a module.
primary value (PV)
Dynamic variable that contains the primary value of Device Variables, which are
direct or indirect process measurements by a HART field device. See
for
more information.
Program mode
In this mode, the controller program is not executing. Inputs are actively
producing data. Outputs are not actively controlled and go to their configured
Program mode state.
remote connection
An I/O connection where the controller establishes an individual connection
with I/O modules in a remote chassis.
removable terminal block (RTB)
Field wiring connector for I/O modules.
removal and insertion under power
(RIUP)
ControlLogix feature that lets you install or remove a module or RTB while
power is applied.
requested packet interval (RPI)
A configurable parameter that defines when the module will multicast data.
Run mode
In this mode, the controller program is executing. Inputs are actively producing
data. Outputs are actively controlled.
secondary value (SV)
Dynamic variable that contains the secondary value of Device Variables, which
are direct or indirect process measurements by a HART field device.
service
A system feature that is performed on user demand.
single-ended
1) Unbalanced, as when one side is grounded. See unbalanced circuit (
)
2) Contrasted with differential (
system side
Backplane side of the interface to the I/O module. In this glossary, see related
entry for field side.
tag
A named area of the controller’s memory where data is stored like a variable.
third value (TV)
Dynamic variable that contains the tertiary, or third, value of Device Variables,
which are direct or indirect process measurements by a HART field device.
timestamping
ControlLogix process that stamps a change in input, output, or diagnostic data
with a time reference indicating when that change occurred.
unbalanced circuit
1) A circuit whose two sides are electrically dissimilar, as when one side is
grounded. 2) Contrasted with balanced circuit (
).