Inovance ME320LN Series Elevator-specialized Inverter User Guide: Operation Panel, Terminal Control and Fault Troubleshooting

1. Introduction

The Inovance ME320LN series is a purpose-built variable-frequency drive (VFD) engineered specifically for elevator traction-machine applications. Manufactured by Shenzhen Inovance Technology Co., Ltd., this inverter drives both permanent magnet synchronous motors (PMSM) and asynchronous induction motors, making it versatile across the full spectrum of modern elevator installations. The series covers a power range from 2.2 kW to 45 kW with a 380 V three-phase input, corresponding to model designations ME320LN-4002-SA through ME320LN-4045-SA.

What distinguishes the ME320LN from general-purpose inverters is its suite of elevator-specific features designed to ensure passenger safety and ride comfort. These include:

• Multi-segment S-curve acceleration and deceleration — four independently configurable S-curve groups, each with adjustable start-segment and end-segment ratios, enabling smooth jerk-limited transitions at every phase of elevator motion.
• Multi-speed floor control — eight programmable speed presets (multi-speed 0–7) selectable via digital input terminal combinations, allowing distinct speeds for inspection, crawling, and high-speed running.
• Brake (抱闸) control interface — dedicated timing parameters for brake open/close sequencing, with feedback monitoring and fault protection.
• Pre-torque compensation — five selectable weighing methods (including digital, analog, and no-weighing zero-servo modes) to prevent car rollback or creep at the instant the brake releases.
• Emergency power operation — support for both 48 V battery and UPS emergency rescue running, ensuring passengers can be evacuated during a mains power failure.
• Direct stopping function — eliminates the traditional crawling phase before leveling, improving running efficiency by calculating a precise deceleration distance to the landing.
• Forced deceleration and overspeed protection — independent up/down speed detection thresholds with configurable action responses.
• Advance door-opening signal — outputs a signal when the car decelerates below a preset frequency during approach to the landing, enabling the door to begin opening before a full stop.

The ME320LN supports three control modes: sensorless vector control (SVC), closed-loop vector control (VC) with encoder feedback, and V/F control. For elevator applications, closed-loop VC is the standard choice because it delivers the precise speed and torque control required for smooth leveling and comfortable ride quality.

2. Operation Panel

The ME320LN is equipped with an LED operation panel that serves as the primary interface for parameter configuration, status monitoring, and basic run commands. Understanding the panel layout and menu structure is essential for commissioning and troubleshooting.

2.1 Panel Keys and Indicators

The panel features six keys, each with context-dependent functions:

The panel also includes LED indicators that show the inverter’s operating state: a running indicator, a stop indicator, and a fault alarm indicator. When a fault occurs, the display shows the corresponding fault code (e.g., Err02) flashing alternately with the fault sub-code.

2.2 Three-Level Menu Structure

Parameters are organized in a three-level hierarchy:

1. Level 1 — Parameter Group: Groups are labeled F0 through FP, each covering a functional category (e.g., F0 = Basic, F1 = Motor, F3 = Start/Stop, F6 = Speed, F7 = Curve, F9 = Protection, FC = Enhanced elevator functions).
2. Level 2 — Function Code: Each group contains numbered function codes (e.g., F0-00, F0-01).
3. Level 3 — Parameter Value: The settable value for the selected function code.

To modify a parameter, press PRG to enter the menu, navigate to the desired group using MF.K, select the function code, then press ENTER to edit the value. After adjusting, press ENTER again to save.

2.3 Status Display Parameters

During operation, the panel can display multiple real-time parameters simultaneously via configurable display settings:

• F8-01 (Running display parameter): A 13-bit bitmap controlling which values are shown during running — including output frequency, target frequency, DC bus voltage, output voltage, output current, AI1/AI2 analog inputs, car load percentage, start compensation current, torque current, and input/output terminal status.
• F8-02 (Stop display parameter): An 8-bit bitmap for values shown at standstill — including target frequency, bus voltage, AI1/AI2, car load, and terminal status.
• F8-00 (Terminal status indicator): Displays the on/off state of all digital input and output terminals using individual LED segments (segments A–G and DP of digits 3, 4, and 5 correspond to DI1–DI10, FM, DO1, DO2, Relay1, Relay2).

2.4 Password Protection

Parameter access can be protected using FP-00 (password setting) and FP-01 (password verification). When a password is set, the user must enter the correct value before modifying parameters. This prevents unauthorized changes to safety-critical elevator settings.

2.5 Fault Record Access

The inverter stores the most recent 11 fault events in parameters F9-14 through F9-69. Each record includes the fault type, sub-code, date, and time. Additionally, the most recent fault captures a snapshot of operating conditions at the moment of failure: set frequency, feedback frequency, DC bus voltage, output voltage, output current, torque current, output power, and input/output terminal states. This diagnostic data is invaluable for root-cause analysis.

3. Terminal Control

In elevator applications, the ME320LN is typically controlled by an external elevator controller via digital and analog terminals rather than the operation panel. Proper terminal wiring and function assignment are critical for safe and reliable operation.

3.1 Main Circuit Terminals

3.2 Main Control Board Terminals

3.3 IO Expansion Board Terminals

When additional I/O is required, an optional expansion board provides:

• DI6–DI10: Five additional digital inputs for functions such as inspection signal, emergency input, direct-stop command, weighing terminals, or motor overheat signal.
• RELAY2: A second relay output, commonly used for brake contactor control.
• PG card pulse interface: A-IN/B-IN (open-collector input from PG card frequency-divider output) and A-OUT/B-OUT (open-collector output) plus A+/A−/B+/B− (differential output) for routing encoder signals to the elevator controller. This is essential when using the direct-stopping function.

3.4 Digital Input Function Assignment

Each DI terminal can be assigned one of 23 functions (values 0–22) via parameters in the F4 group. Key elevator-specific functions include:

3.5 Output Terminal Functions

Output terminals (FM, DO1, DO2, Relay1, Relay2) can be assigned one of 19 functions (values 0–18) via the F5 group. Common assignments include: run-ready signal, zero-speed signal, fault output, brake contactor control, advance door-opening signal, light-load output (for emergency direction selection), and frequency arrival (FDT) output.

4. Parameter Settings (Elevator-Specific)

4.1 Control Mode and Command Source

• F0-00 (Control mode): 0 = SVC (sensorless vector), 1 = VC (closed-loop vector with encoder), 2 = V/F. For elevator use, VC (value 1) is standard.
• F0-01 (Command source): 0 = operation panel, 1 = terminal. Elevator applications use terminal control (value 1).
• F0-02 (Speed source): 0 = digital preset (F0-03), 1 = multi-speed, 2 = AI1, 3 = AI2. Most elevator installations use multi-speed (value 1) or analog input (value 2).

4.2 Motor and Encoder Parameters (F1, FA Groups)

Correct motor parameter setup is the foundation of stable vector control. Key parameters include:

• F1-00 (Encoder type): 0 = ABZ incremental, 1 = SIN/COS, 2 = UVW commutation. Must match the physical encoder and PG card.
• F1-01 through F1-09: Motor rated power, voltage, current, frequency, RPM, stator resistance, leakage inductance, etc.
• F1-11 (Motor tuning): 0 = no tuning, 1 = static tuning (no rotation), 2 = rotating tuning (no load), 3 = rotating tuning (with load). For synchronous motors, the encoder initial angle is learned during this process.
• F1-25 (Motor type): 0 = asynchronous, 1 = synchronous (PMSM).
• FA-00 (Encoder pulses per revolution): Must exactly match the encoder specification. Incorrect setting causes overcurrent faults.
• FA-03 (Encoder magnetic pole angle): Learned during tuning; essential for PMSM control. Must be set before switching F0-01 from 0 to 1.
• FA-06 (PG card frequency-divider ratio): Used when routing encoder signals through the PG card to the elevator controller for direct-stopping.

4.3 Start/Stop and Pre-Torque (F3 Group)

The F3 group governs the critical start and stop sequence that directly affects ride comfort and safety:

• F3-01 to F3-08: Timing parameters for the run contactor, brake, and zero-speed hold — controlling the sequence from run command to brake opening, and from zero-speed detection to brake closing at stop.
• F3-09 (Pre-torque setting method): 0 = no compensation, 1 = digital weighing (4-terminal), 2 = analog weighing (AI1), 3 = analog weighing (AI2), 4 = DI weighing (2-terminal), 5 = no-weighing zero-servo mode.
• F3-10 (Pre-torque offset): Set to the elevator’s balance coefficient (typically 40–50%). This determines the compensation breakpoint between up and down directions.
• F3-11 (Pre-torque gain): Adjusts compensation strength. Typically around 0.6; tune by observing whether the car creeps when the brake opens.
• F3-18, F3-19 (Analog weighing empty/full-load values): Calibrated via the FU-17 AI1 sampling value at empty and full car conditions, or auto-learned via F3-20/F3-21.

4.4 Multi-Speed and Curve Selection (F6, F7 Groups)

The ME320LN provides eight programmable speed presets and four S-curve groups, offering maximum flexibility for elevator speed profiles:

Each S-curve group contains four parameters:

Groups 2, 3, and 4 follow the same pattern (F7-04–F7-07, F7-08–F7-11, F7-12–F7-15). The S-curve start segment controls the rate of change of acceleration (jerk) at the beginning of the speed transition, while the end segment controls jerk at the conclusion. Between these two segments, acceleration is constant. This structure produces the smooth, comfortable motion profile expected in modern elevator systems.

A typical elevator application assigns speeds as follows: inspection = multi-speed 2 at 10 Hz with S-curve 4; crawling = multi-speed 3 at 3 Hz with S-curve 3; high-speed = multi-speed 7 at 48 Hz with S-curve 1.

4.5 Enhanced Elevator Functions (FC Group)

• FC-00 (Command abnormal action): Determines response when FWD/REV commands become invalid simultaneously — 0 = normal deceleration stop, 1 = immediate output cutoff.
• FC-01 (Abnormal deceleration time): 0–300 s; used for forced deceleration and abnormal stops.
• FC-02/FC-03 (Up/down forced deceleration level): When the forced deceleration switch triggers and the running frequency exceeds this threshold, the inverter decelerates at FC-01 time. Default: 45.00 Hz.
• FC-04 (Advance door-opening level): Outputs a door-open signal when decelerating frequency drops below this value (default 5.00 Hz), enabling the door to start opening before the car fully stops.
• FC-05–FC-08 (FDT frequency detection): Two independent frequency detection thresholds with configurable hysteresis, used for frequency-arrival output signals.
• FC-09/FC-10 (Overspeed level/delay): Triggers overspeed protection when running frequency exceeds a percentage of maximum frequency (default 115%) for longer than the delay (default 1.0 s).
• FC-12/FC-13 (Speed deviation level/delay): Protects when feedback frequency deviates from setpoint by more than the threshold (default 30%) for the specified duration.

4.6 Direct Stopping Function (F7-17, F7-18)

The direct stopping function eliminates the crawling phase before leveling. The elevator controller sends a direct-stop command (DI function 22) at a fixed distance from the landing. The inverter then calculates the required deceleration profile to stop precisely at the landing position. Key parameters:

• F7-17 (Direct stop setting distance): The distance from the landing at which the direct-stop command is issued (adjustable 0.0–6553.5 mm). If the car stops short, increase F7-17; if it overshoots, decrease it.
• F7-18 (Direct stop actual distance): A read-only monitoring parameter showing the actual distance traveled during the last direct-stop sequence, used for commissioning verification.
• F8-03 (Elevator rated speed): The car speed at motor rated frequency (e.g., 1.600 m/s). This value is used in the deceleration distance calculation.

The deceleration distance from the speed-change point to stop is calculated as:

5. Communication

5.1 RS-485 Interface

The ME320LN provides an RS-485 serial communication interface via the MOD+ and MOD− terminals on the main control board. This interface allows connection to a host computer, PLC, or building management system for remote monitoring and parameter read/write operations.

The FB parameter group is designated for communication configuration but is currently reserved in the standard firmware, indicating that communication protocol details may be customized for specific OEM requirements. The SPI communication link between the control board and the driver board is continuously monitored, with Err55 (DSP communication protection) triggered if the internal connection fails.

5.2 Communication Cable Requirements

For reliable RS-485 communication in the electrically noisy elevator machine room environment, the following practices are mandatory:

• Use shielded twisted-pair cable with a twist pitch of 20–30 mm.
• The shield must be grounded at a single point to prevent ground loops.
• Route communication cables at least 500 mm away from motor power cables and brake resistor cables. Where crossing is unavoidable, maintain a 90-degree crossing angle.
• Install matching termination resistors at both ends of the communication bus to prevent signal reflection.
• Add a dedicated communication common ground wire alongside the RS-485 pair.

5.3 Communication Quality Monitoring

The inverter provides monitoring parameters (in the FU group) that display the communication quality between the control board and driver board on a scale of 0–9. A value of 0 indicates excellent quality; higher values indicate increasing interference. If communication quality degrades, investigate grounding, cable shielding, and routing.

5.4 EMC Considerations for Communication

As a Class C2 EMC device (per EN 61800-3:2004), the ME320LN can generate electromagnetic interference that affects nearby communication equipment. To mitigate:

• Install an external EMC input filter between the power source and the inverter’s R/S/T input, selected per the recommended model table.
• Connect the filter and inverter to the same metal mounting plate with low-impedance grounding.
• Use shielded motor cables with braided copper shielding density greater than 90%.
• For motor cable lengths exceeding 100 m, install an output reactor or filter.

6. Fault Codes

The ME320LN implements over 50 protection functions. When a fault is detected, the inverter stops output, activates the fault relay, and displays the fault code on the operation panel. Most faults can be reset via the STOP key or a digital reset terminal; however, Err16, Err17, and Err33 require a full power cycle and cannot be reset by software.

6.1 Overcurrent and Overvoltage Faults

6.2 Power and Hardware Faults

6.3 Encoder and Motor Faults

6.4 Elevator-Specific Protection Faults

6.5 Other Faults

6.6 Common Troubleshooting Scenarios

Beyond fault codes, the following operational issues are commonly encountered:

• No display on power-up: Check input voltage matches rating; inspect three-phase rectifier bridge; check CHARGE indicator lamp — if off, fault is likely in the rectifier or buffer resistor; if on, suspect switching power supply.
• Circuit breaker trips on power-up: Check for ground or short between input phases; inspect rectifier bridge for breakdown.
• Motor does not rotate after run command: Check for balanced three-phase output at U/V/W — if balanced, suspect motor or mechanical jam; if unbalanced, suspect drive board or output module; if no output, suspect output module failure.
• Circuit breaker trips during running: Check for short between output modules; check motor leads for short or ground; if intermittent and motor cable is long, consider adding an output AC reactor.

For faults that persist after following the troubleshooting steps above, contact the local Inovance distributor or service center with the fault code, sub-code, and the diagnostic snapshot data from parameters F9-54 through F9-69. This information enables the service engineer to diagnose the issue efficiently.

Source: Inovance ME320LN Series Elevator-specialized Inverter User Manual (Document No. 19010295A02). Copyright Shenzhen Inovance Technology Co., Ltd.