Siemens PERFECT HARMONY GENIII/E Series User Manual page 117

Perfect Harmony GENIII/e User's Manual Glossary of Terms
Relay - A relay is an electrically controlled device that causes electrical contacts to change their status. Open contacts
A
will close and closed contacts will open when rated voltage is applied to the coil of a relay.
Resonance avoidance - Resonance avoidance is a feature that allows the operator to program up to 3 mechanical
system frequencies that the drive will "skip over" during its operations.
RS232C - RS232C is a serial communications standard of the Electronics Industries Association (EIA).
Setpoint - Setpoint is the desired or optimal speed of the VFD to maintain process levels (speed command).
Slip - Slip is the difference between the stator electrical frequency of the motor and the rotor mechanical frequency of
the motor, normalized to the stator frequency as shown in the following equation.:
- ω
Slip =ω
S R
ω
S
Slip is the force that produces torque in an induction motor. Slip can also be defined as the shaft power of the motor
divided by the stator input power.
Slip compensation - Slip compensation is a method of increasing the speed reference to the speed regulator circuit
(based on the motor torque) to maintain motor speed as the load on the motor changes. The slip compensation circuit
increases the frequency at which the inverter section is controlled to compensate for decreased speed due to load
droop. For example, a motor with a full load speed of 1760 rpm has a slip of 40 rpm. The no load rpm would be 1800
rpm. If the motor nameplate current is 100 A, the drive is sending a 60 Hz wave form to the motor (fully loaded); then
the slip compensation circuit would cause the inverter to run 1.33 Hz faster to allow the motor to operate at 1800 rpm,
which is the synchronous speed of the motor.
SMC - Is an acronym for Synchronous Motor Control - which is one of six control modes in the NXG drive.This
mode computes the rotational speed similarly to open-loop vector control, and controls the field reference or the
synchronous motor as in closed-loop synchronous motor control.
SOP - (1) SOP is an acronym for Sum Of Products. The term "sum-of-products" comes from the application of
Boolean algebraic rules to produce a set of terms or conditions that are grouped in a fashion that represents parallel
paths (ORing) of required conditions that all must be met (ANDing). This would be equivalent to branches of
connected contacts on a relay logic ladder that connect to a common relay coil. In fact, the notation can be used as a
shortcut to describe the ladder logic. (2) SOP, when used as a filename extension, refers to System Operating
Program.
SOP Utilities - The program within the Siemens LD A ToolSuite used for converting between text and machine
loadable code. It can also be used for uploading and downloading files over the RS232 connection.
Stop mode - Stop mode is used to shut down the drive in a controlled manner, regardless of its current state.
Submenus - A submenu is one of four components found in the Perfect Harmony menu system. Submenus are nested
menus (i.e., menus within other menus). Submenus are used to logically group menu items based on similar
functionality or use.
Synchronous speed - Synchronous speed refers to the speed of an AC induction motor's rotating magnetic field. It is
determined by the frequency applied to the stator and the number of magnetic poles present in each phase of the stator
windings. Synchronous Speed equals 120 times the applied Frequency (in Hz) divided by the number of poles per
phase.
System Operating Program - The functions of the programmable inputs and outputs are determined by the default
system program. These functions can be changed by modifying the appropriate setup menus from the front keypad
and display. I/O assignments can also be changed by editing the system program (an ASCII text file with the
extension .SOP), compiling it using the compiler program, and then downloading it to the controller through its serial
port, all by utilizing the SOP Utility Program with the Siemens LD A ToolSuite.
SOP Utilities - see ToolSuite definition.
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