User`s manual

535 User's Manual Appendix 6 A-21
Glossary
setpoint, deviation from: The
difference of the number of units
between the current process variable
and the setpoint.
setpoint, ramping: A setpoint which
is determined by the ramp function of
the controller where over time the
controller variable reaches a desired
value.
setpoint, target: The end point of the
ramp function.
set up: Also called configuration,
selection of hardware devices and
software routines that function
together.
sheds: In serial communications,
when the signal is lost.
slidewire position proportioning:
An output algorithm that utilizes a
slidewire feedback signal to
determine the actual position of the
actuator being controller.
solid state relay: (see relay, solid
state)
SSR drive: A D.C. on/off signal
output for controlling a solid state
relay.
staged outputs: The set up of two
analog outputs, where one analog
output varies its signal over a portion
of the PID output range, and the
second analog output then varies its
signal over the remainder of the PID
output range.
static discharge: Undesirable
current resulting from the discharge
of electrostatic energy.
station address: The unique
identifier assigned to a device for
communications.
thermocouple: Temperature
sensing device that is constructed of
two dissimilar metals wherein a
measurable, predictable voltage is
generated corresponding to
temperature.
thermocouple break protection:
Fail-safe operation that assures
desired output upon an open
thermocouple condition.
thermocouple upscale burnout (
▲▲
▲▲
▲):
Jumper position that determines
whether, when a thermocouple fails,
its output is replaced by a millivoltage
which will match the thermocouple’s
maximum value. The jumper
connector should be placed in the TC
▲▲
▲▲
▲ position.
thermocouple downscale burnout (
▼▼
▼▼
▼):
Jumper position that determines
whether, when a thermocouple fails,
its output is replaced be a millivoltage
which will match the thermocouple’s
minimum value. The jumper
connector should be placed in the TC
▼▼
▼▼
▼ position.
three mode control: (See control
action PID)
time proportioning control: A
control algorithm that expresses
output power (0–100%) as a function
of percent ON versus percent OFF
within a preset cycle time.
time proportioning output: A
controller output assigned by
software to facilitate time proportional
control (typically a relay, SSR, or
SSR Drive output).
tracking: A function that defines
whether the local setpoint will track
the remote setpoint. When the
controller is transferred to a local
setpoint, that local setpoint value will
match the remote process value
when the transfer occurs.
transmitter (2-wire): A device used
to transmit data via a two wire current
loop. A two-wire transmitter is loop
powered.
transmitter (4-wire): A device used
to transmit data via a current loop or
a DC voltage. A 4-wire transmitter
uses 2 wires for data and 2 wires for
power.
triac: Solid state switching device
used to switch alternating current
signals on and off. Triac circuits are
sometimes referred to as solid state
relays (SSR).
trip point: Value which determines
when that set of PID values becomes
active.
velocity position proportioning:
This is a control technique where
valve position is determined by
calculating the amount of time it takes
to open/close a valve by moving the
valve for a portion of that time.
windup: Saturation of the integral
mode of a controller developing
during times when control cannot be
achieved, which causes the
controlled variable to overshoot its
setpoint when the obstacle to control
is removed.
wild stream: In mixing applications
that require materials to be mixed to
a desired ratio, this is the one part of
the material that is uncontrolled.