Siemens SINAMICS PERFECT HARMONY GH180 Function Manual page 328

Glossary
LVD
LVD is an acronym for Low Voltage Directive, a safety directive in the EU.
Lvl RH
This term refers the two security fields associated with each parameter of the system. These
fields allow the operator to individually customize specific security features for each menu
option (submenu, parameter, pick list, and function). These fields are shown in parameter
dumps and have the following meanings. Lvl is the term for the security level. Setting R=1
blocks parameter change, and setting H=1 hides the menu option from view until the
appropriate access level has been activated.
Memory
Memory is the working storage area for the drive that is a collection of RAM chips.
NEMA 1 and NEMA 12
NEMA 1 is an enclosure rating in which no openings allow penetration of a 0.25-inch diameter
rod. NEMA 1 enclosures are intended for indoor use only. NEMA 12 is a more stringent NEMA
rating in which the cabinet is said to be "dust tight" (although it is still not advisable to use
NEMA 12 in conductive dust atmospheres). The approximate equivalent IEC rating is IP52.
Normally closed (NC)
Normally closed refers to the contact of a relay that is closed when the coil is de-energized.
Normally open (NO)
Normally open refers to the contact of a relay that is open when the coil is de-energized.
OLTM
An acronym for Open Loop Test Mode, one of the control modes of the 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 the control modes of the 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.
328
NXGpro Communication
Function Manual, AB, A5E33486415A