Functions Siemens

Setpoint inputs

Setpoints can be input both internally and externally, i.e. internally as a fixed setpoint or motorized potentiometer setpoint and externally via the communications interface or an analog input on the customer terminal strip. The internal fixed setpoint and the motorized potentiometer setpoint can be switched over or adjusted using control commands via all interfaces.

Autotuning function

Thanks to the autotuning function (automatic measurement of the motor stator resistance), the closed-loop drive control can be commissioned and optimized faster and more easily.

Random pattern

Pulse pattern generation with or without random pattern can be selected. The purpose of this function is to prevent dominant clock frequency noise in the motor.

Ramp-function generator

A convenient ramp-function generator with separately adjustable and switchable ramping times, together with adjustable and switchable rounding times in the lower and upper speed ranges (transition roundings 1 to 4), allows the drive to be smoothly accelerated and braked. As a consequence, this avoids the drive train from being overloaded and reduces the stress on mechanical components. The down ramps can be parameterized separately for quick stop. In addition, all parameters can be switched over for special operating ranges.

Overvoltage controller

The overvoltage limiting controller automatically prevents overvoltages in the DC link if the down ramp is too short, for example. This may also extend the set ramp-down time.

Mains supply backup

In the event of supply voltage dips, the kinetic energy of the rotating drive is used to buffer the DC link so as to prevent fault trips. The converter remains operational as long as the drive can provide regenerative energy as a result of its motion and the DC link voltage does not drop below the trip threshold. When the line supply recovers within a parameterizable time, the drive is again accelerated up to its setpoint speed.

Undervoltage behavior

The operational performance of the frequency converter under line undervoltage conditions can be influenced to a large extent.
The automatic restart function switches the drive on again when the power is restored after a power failure, and ramps up to the current speed setpoint. The automatic restart function is successful only if the power failure does not last longer than the parameterized T restart time.

Synchronization

It is possible to synchronize the SINAMICS G180 converter with a motor that is still turning and to accelerate the motor to the specified setpoint.

Slip compensation

An automatic slip compensation function improves the speed accuracy of drives that are not equipped with a speed encoder.

Process control

The integrated process controller can be used to implement simple control functions, e.g. level control or volumetric flow control.
It is designed as a PID controller with separately settable P, I and D components.

Logic elements

The "Logic elements" function can be used to generate modal signals and to combine signals using logic.

Message generators

Messages can be generated subject to predefined conditions.

Parameter switches

A parameter switch can be used to switch a parameter from its original value to an alternative value.

Automatic acknowledgement function

Fault messages can be acknowledged fully automatically if required.

Display

The bilingual, four-line graphical display with membrane keyboard on the converter shows operational messages, alarms and fault messages in plain text. The converter can be operated locally by means of this display.

Event memory

A comprehensive memory function for storing the last 64 events, including actual values recorded prior to and during each event, aids the evaluation and analysis of faults.

Time synchronization and operating hours counters

Timing functions can be synchronized with an external clock via digital inputs. Two different counters, one for frequency converter operating hours and the other for fan operating hours, can supply important information to the service engineer.

Motor protection

Motor protection through evaluation of a KTY84, PTC or Pt100 temperature sensor. When a KTY84 sensor is connected, the limit values can be set for alarm or shutdown. When a PTC thermistor is connected, the system reaction to triggering of the thermistor (alarm or shutdown) can be defined.

Motor blocking protection

A blocked motor is detected and can be protected against thermal overloading by a fault trip.

Noise reduction

Optimization of the pulse pattern can minimize motor noise emissions and also reduce motor losses.

Brake optimization

An oversaturation control system is provided to ensure optimum braking performance without the need for any additional equipment.
A parameterizable DC braking function is also provided to permit precise deceleration down to zero speed.

Operational reliability

In order to ensure smooth reliable operation, the converter is equipped with an automatic overload time adaptation function and stall protection implemented by a tried-and-tested current limitation control system.

Fault detection

Automatic monitoring for irregularities in operation, e.g. overspeed, underspeed or no-load. These conditions can be detected and signaled by appropriate alarms.

Fault suppression

Fault messages and fault trips initiated by fault messages can be suppressed (e.g. for smoke extraction motors).

Power unit protection

Description

Ground fault monitoring at output end

A ground fault at the output end is detected by a total current monitor and results in shutdown in grounded-neutral systems.

Insulation monitoring

The insulation can be monitored for ground faults on converters operating on a non-grounded power supply system.

Current asymmetry monitoring at output end

A current symmetry monitoring system detects hazardous current unbalances and initiates a fault trip if necessary.

Electronic short-circuit protection at the output end

A short-circuit at the output (e.g. at the converter output terminals, in the motor cable or in the motor terminal box) is detected and the converter shuts down with "fault".

Thermal overload protection

When the overtemperature threshold monitor responds, an alarm is output initially and the clock frequency is reduced. If the temperature continues to rise, the current limit values are lowered in order to reduce the thermal load. Once the cause of the fault has been eliminated (e.g. cooling has been improved), the original operating values are automatically resumed.