Siemens 6SR41 series Product User Manual page 193

OLTM
An acronym for Open Loop Test Mode - One of six control modes of the NXG drive.
OLVC
An acronym for Open Loop Vector Control, also known as Encoderless Vector Control.
OLVC is a flux vector control that is one of six control modes of the NXG drive. The drive
computes the rotational speed of the rotor and uses it for speed feedback.
OOS
OOS is an abbreviation for out of saturation - a type of fault condition in which a voltage drop
is detected across one of the IGBTs during conduction. This can indicate that the motor is
drawing current too rapidly or in excess.
OR
OR is a logical Boolean function whose output is true if any of the inputs is true. In SOP
notation, OR is represented as "+".
Parameter
A parameter is one of four items found in the Perfect Harmony menu system. Parameters
are system attributes that have corresponding values that can be monitored or, in some
cases, changed by the user.
PED
PED is an acronym for pressure equipment directive, a directive of the EU relating to
pressure vessels.
Pick list
A pick list is one of four items found in the Perfect Harmony menu system. Pick lists are
parameters that have a finite list of pre-defined "values" from which to choose, rather than a
value range used by parameters.
PID
PID is an acronym for proportional + integral + derivative, a control scheme used to control
modulating equipment in such a way that the control output is based on (1) a proportional
amount of the error between the desired setpoint and the actual feedback value, (2) the
summation of this error over time, and (3) the change in error over time. Output contributions
from each of these three components are combined to create a single output response. The
amount of contribution from each component is programmable through gain parameters. By
optimizing these gain parameters, the operator can "tune" the PID control loop for maximum
efficiency, minimal overshoot, quick response time, and minimal cycling.
Product User Manual
Operating Instructions, Version AE 12/2009, A5E01454341C
Glossary
191