SD320L Closed-Loop Elevator Inverter with Sin/Cos 1387 PG Card

Product Overview

The SD320L is a closed-loop elevator inverter developed for speed and torque control in lift systems using encoder feedback. It supports compatible asynchronous AC induction motors and permanent magnet synchronous motors, allowing the drive configuration to be matched to geared or gearless elevator systems.

Multiple PG card options are available for AB, ABZ, EnDat 1313, and Sin/Cos 1387 encoder signals. When equipped with the appropriate card, the inverter receives motor position or speed feedback and uses this information to regulate motor output in real time.

The SD320L combines closed-loop vector control, motor auto-tuning, flexible S-curve settings, startup pre-torque compensation, brake and contactor control, speed monitoring, emergency evacuation support, and elevator-specific fault detection. Available configurations cover three-phase 200–240V and three-phase 380–480V power systems.

The inverter controls the elevator motor but does not replace the elevator controller, mechanical brake, overspeed governor, safety gear, door interlocks, or other safety devices required by the complete lift system.

Closed-Loop Vector Control

Encoder Feedback Control

In a closed-loop system, the motor encoder returns actual speed or position information to the inverter through a compatible PG card. The drive compares this feedback with the commanded value and adjusts motor current, torque, and speed accordingly.

Compared with encoder-free control, correctly commissioned closed-loop vector control can provide:

• More accurate low-speed regulation

• Improved response to load changes

• Controlled starting torque

• More stable speed transitions

• Better coordination at starting and stopping

• More consistent leveling performance

• Improved control of geared and gearless motors

Actual performance depends on the motor, encoder resolution, PG card, mechanical system, controller commands, brake timing, parameter settings, and commissioning quality.

Low-Speed Elevator Operation

Elevators require controlled operation during startup, inspection, deceleration, and floor approach. Encoder feedback allows the SD320L to monitor actual motor movement during these low-speed stages.

Closed-loop control does not independently determine the car position or floor location. Floor selection, leveling commands, door operation, terminal limits, and safety logic remain the responsibility of the elevator controller and associated sensors.

Startup Pre-Torque Compensation

Before the mechanical brake opens, the drive can establish motor torque according to the configured startup sequence. This helps reduce unintended rollback or abrupt movement when the brake is released.

Pre-torque parameters must be coordinated with:

• Car load

• Counterweight ratio

• Motor type

• Traction arrangement

• Brake opening delay

• Torque direction

• Encoder direction

• Elevator controller signals

Incorrect torque direction or brake timing can cause unexpected motor movement. Initial testing should therefore be performed under controlled commissioning conditions.

PG Card and Encoder Options

The SD320L supports multiple encoder interfaces through dedicated PG card options.

Sin/Cos 1387 Feedback

The Sin/Cos 1387 PG card is intended for compatible encoders used in elevator motor control. The card processes the encoder feedback signals and transfers the required motor feedback information to the SD320L.

Before selecting this option, provide:

• Complete encoder manufacturer and model

• Encoder interface type

• Encoder supply voltage

• Sin/Cos signal specification

• Number of signal periods or pulses

• Motor type

• Encoder cable definition

• Connector pinout

• Cable length

• Shielding and grounding method

The term “1387 encoder” alone is not sufficient to confirm compatibility. The exact electrical interface and encoder documentation should be reviewed before ordering.

EnDat 1313 Feedback

EnDat 1313 and Sin/Cos 1387 encoders do not necessarily use the same communication and feedback method. The correct PG card must be selected for the installed encoder.

A PG card should not be chosen only because the connector appears mechanically compatible. Signal type, power supply, communication, pin definition, grounding, and inverter firmware must all be checked.

Encoder Installation

Encoder cables should be routed separately from motor output cables and other high-current conductors. Shielding and grounding should follow the inverter, encoder, and control-panel requirements.

During commissioning, confirm:

1. Encoder power supply

2. Encoder signal type

3. PG card installation

4. Cable pin assignment

5. Motor rotation direction

6. Encoder feedback direction

7. Feedback value at low speed

8. Absence of signal-loss or speed-deviation faults

Asynchronous and PMSM Motor Control

Asynchronous Induction Motors

The SD320L can control compatible asynchronous AC induction motors used in geared elevator systems. Motor nameplate data and encoder information must be entered before auto-tuning.

Required motor data normally include:

• Rated voltage

• Rated current

• Rated power

• Rated frequency

• Rated speed

• Power factor

• Encoder type

• Encoder pulse or signal data

Permanent Magnet Synchronous Motors

The inverter also supports compatible permanent magnet synchronous motors commonly used in gearless elevator systems.

PMSM commissioning requires additional attention because correct rotor-position and encoder information are essential for torque production. The exact motor and encoder combination should be confirmed before selecting the inverter and PG card.

Motor identification and initial rotation tests must be conducted according to the applicable commissioning procedure. Incorrect encoder offset, wiring, phase sequence, or feedback direction may cause abnormal torque or startup failure.

Motor Auto-Tuning

The SD320L supports static and complete motor auto-tuning.

Static auto-tuning may be used when the motor cannot rotate freely, subject to the limitations specified in the operating manual. Complete auto-tuning generally requires controlled motor rotation and must only be performed when the elevator is placed in an appropriate commissioning state.

Before auto-tuning:

• Verify motor wiring

• Confirm encoder wiring

• Check the mechanical brake

• Isolate normal passenger operation

• Confirm the car and counterweight condition

• Enter accurate motor data

• Follow the applicable elevator safety procedure

Elevator Motion Control

Flexible S-Curve Settings

The SD320L provides flexible startup curves, multi-segment S-curve settings, and four groups of acceleration and deceleration times.

These settings allow the commissioning technician to coordinate:

• Starting response

• Normal acceleration

• Constant-speed travel

• Deceleration

• Leveling approach

• Final stopping

• Inspection operation

• Emergency operation

An S-curve reduces the rate of acceleration change, but ride comfort cannot be determined by the inverter setting alone. Guide-rail condition, traction components, brake operation, car balance, controller commands, and mechanical installation also affect passenger experience.

Multiple Speed References

The drive supports multiple speed sources, including multi-speed and analog settings. The final command arrangement should be defined according to the elevator controller.

Speed stages may be assigned for:

• Inspection speed

• Creep speed

• Leveling speed

• Normal travel

• Reduced-speed operation

• Emergency evacuation

Signal priority and transition logic should be checked to prevent conflicting commands.

Slow-Down Judgment

The SD320L provides elevator-related slow-down judgment functions. These functions support the control sequence but do not replace terminal limit switches, floor-position signals, or other independent safety devices.

The required deceleration distance should account for car speed, load, brake condition, traction system, controller logic, and applicable elevator standards.

Door Pre-Opening Support

Door pre-opening may be supported as part of a properly designed elevator system. This function must only operate when all required speed, position, leveling-zone, brake, controller, and safety conditions are satisfied.

The inverter alone must not be used as the only device that determines whether door opening is safe.

Brake and Contactor Control

Brake Contactor Control

The SD320L provides functions for coordinating motor torque with mechanical brake operation. A typical sequence includes:

1. Receive the run command.

2. Establish the required motor current or torque.

3. Issue the brake release command.

4. Confirm the brake or contactor feedback.

5. Accelerate according to the selected curve.

6. Decelerate at the destination.

7. Reduce speed to the stopping stage.

8. Apply the mechanical brake.

9. Remove motor torque after the required delay.

The exact sequence must be defined by the elevator controller and system design.

Output Contactor Control

The inverter supports output-contactor control and contact-stuck detection. An output contactor must not be opened while the inverter is actively supplying motor current unless the approved safety sequence specifically requires it.

Improper contactor operation can generate faults or damage electrical components.

Enable Detection

Enable detection helps confirm that the required operating permission is present before motor output begins. Enable logic should be coordinated with the elevator controller, safety circuit, brake feedback, and contactor status.

Emergency Evacuation at Power Failure

The product page states that the SD320L supports emergency evacuation using a 48V battery power supply.

This function may allow a compatible elevator system to move toward a designated floor or safe release position after normal AC power is lost. The complete emergency system may require a battery, switching equipment, controller logic, brake supply, door power, charging circuit, and other external components.

Before applying this function, confirm:

• Supported SD320L models

• 48V input terminal and permitted range

• Battery type and capacity

• Required evacuation direction

• Maximum load

• Motor compatibility

• Permitted travel speed

• Brake power arrangement

• Elevator controller sequence

• Number of expected rescue operations

The phrase “supports 48V emergency evacuation” should not be interpreted as meaning the inverter alone forms a complete automatic rescue device.

Setup and Commissioning

Pre-Commissioning Checks

Before energizing the inverter, verify:

• Input voltage and phase

• Protective grounding

• Motor wiring

• Motor insulation condition

• Brake circuit

• Contactor circuit

• PG card model

• Encoder wiring

• Encoder power supply

• Control terminal assignments

• Emergency stop circuit

• Controller communication

• Braking resistor specification

Recommended Commissioning Sequence

1. Confirm the SD320L voltage and current rating.

2. Enter the complete motor nameplate data.

3. Select asynchronous motor or PMSM control.

4. Select the installed PG card and encoder type.

5. Confirm encoder resolution and signal settings.

6. Perform the applicable motor auto-tuning procedure.

7. Test motor and encoder directions at low speed.

8. Verify brake release and closing timing.

9. Test inspection operation.

10. Configure startup pre-torque.

11. Adjust acceleration, deceleration and S-curves.

12. Test normal travel under controlled load.

13. Verify leveling and stopping response.

14. Test fault handling and emergency operation.

15. Review operating current, speed feedback and fault records.

Passenger service should not begin until the complete elevator system has passed the required inspection and safety testing.

Drive and Elevator Protection

The SD320L includes elevator-related monitoring and protection functions such as:

• Overspeed protection

• Speed-deviation detection

• Encoder feedback monitoring

• Brake-contactor control

• Output-contactor control

• Contactor-stuck detection

• Motor-overheat detection

• Enable detection

• Drive overcurrent protection

• Drive overvoltage protection

• Undervoltage protection

• Overload protection

• Inverter overtemperature protection

When a fault occurs, the technician should identify the root cause before resetting the inverter. Repeatedly clearing a speed-deviation or encoder fault without checking the encoder, motor direction, brake, and mechanical load may create additional risk.

System Safety Boundary

The SD320L controls motor operation but does not replace:

• Mechanical brake

• Overspeed governor

• Safety gear

• Door interlocks

• Landing-door locks

• Terminal limit switches

• Final limit switches

• Emergency stop circuit

• Load-monitoring system

• Inspection controls

• Elevator safety controller

• Other code-required safety components

Safety functions must be implemented and validated according to the applicable elevator regulations.

Elevator Applications

Villa Elevators

The SD320L can be applied to compatible villa elevators requiring encoder-based motor control. Selection should consider available power, motor type, travel height, rated speed, capacity, and rescue requirements.

Residential Passenger Elevators

Closed-loop control supports residential lift systems where controlled starting, speed transitions, stopping, and leveling are required under changing passenger loads.

Commercial Elevators

Commercial buildings may require more frequent starts, higher traffic levels, and closer coordination with the elevator controller. Drive current, thermal duty, braking energy, and operating frequency should be assessed for the project.

Cargo Elevators

Cargo lifts can produce large and changing load conditions. The inverter should be selected using motor current, overload demand, load imbalance, travel speed, braking duty, and required starting torque.

Geared Elevator Systems

Compatible asynchronous motors with incremental encoder feedback can be used in geared elevator configurations. The PG card must match the installed encoder.

Gearless Elevator Systems

Compatible PMSMs with Sin/Cos 1387, EnDat 1313, or another supported encoder may be used in gearless systems. Motor and encoder documentation should be reviewed together before confirming the configuration.

Technical Specifications

General Performance

Available Models

Electrical Data

The drive should be selected according to motor rated current and overload requirements, not only by comparing the motor kW with the model name.

Quality and Engineering Support

The SD320L uses a separated air-duct structure and conformal-coating process. The original page also lists built-in braking and DC-reactor functions, subject to confirmation for each model.

IFIND provides technical support for:

• Inverter model selection

• Asynchronous motor matching

• PMSM matching

• PG card selection

• Encoder compatibility review

• Motor auto-tuning

• Brake-sequence configuration

• S-curve adjustment

• Emergency evacuation setup

• Fault diagnosis

• Elevator controller integration

For project evaluation, customers should provide the motor nameplate, encoder datasheet, elevator load, rated speed, traction arrangement, controller signals, input supply, braking resistor requirements, and emergency rescue design.

FAQs

What is the difference between open-loop and closed-loop elevator control?

Closed-loop control uses encoder feedback to monitor actual motor operation. This generally provides better low-speed response and speed regulation than encoder-free control. Open-loop control does not require an encoder but cannot provide the same feedback-based correction.

Is a Sin/Cos 1387 PG card included as standard?

The original page lists several PG card options. The required card should be confirmed in the quotation because AB, ABZ, EnDat 1313, and Sin/Cos 1387 interfaces are different.

Can the SD320L control an asynchronous motor?

Yes. It supports compatible asynchronous AC induction motors when the motor, encoder, voltage, current, and PG card are correctly matched.

Can it control a permanent magnet synchronous motor?

Yes. The page states that compatible PMSMs are supported. The motor parameters, encoder interface, rotor-position information, and commissioning method must be confirmed.

Can the same PG card be used for every encoder?

No. The PG card must match the encoder’s signal type, voltage, pinout, resolution, communication method, and cable.

Does every Heidenhain encoder use the 1387 interface?

No. Heidenhain manufactures encoders with different interfaces. The complete encoder model and datasheet are required before selecting a PG card.

What information is needed to select the correct PG card?

Provide the encoder manufacturer, complete model, signal type, supply voltage, pulse or signal-period data, connector pinout, motor model, and cable length.

Does the SD320L include a braking unit?

The original product page states that a braking unit is built in. However, this should be confirmed for the exact power model, together with the required external braking resistor.

Can the inverter perform emergency rescue during a power failure?

The page states that it supports evacuation with a 48V battery supply. The complete rescue configuration, battery capacity, controller sequence, brake supply, permitted load, and supported models must be confirmed.

Does the inverter replace the elevator controller?

No. It regulates motor speed and torque. The elevator controller manages floor logic, travel commands, doors, brake commands, position signals, rescue logic, and the safety sequence.

Why does an encoder-direction fault occur?

Possible causes include reversed encoder channels, incorrect motor direction, wrong PG card selection, incorrect encoder parameters, wiring faults, poor shielding, signal loss, or an incorrect PMSM rotor-position setting.

How should the drive size be selected?

Use motor rated current, overload demand, elevator capacity, rated speed, counterweight ratio, motor type, braking duty, travel frequency, and installation temperature. Motor power alone is insufficient.