Inovance CS710 Series Crane Dedicated Inverter User Guide: Operation Panel, Hoisting Control, Safety Functions and Fault Troubleshooting

The Inovance CS710 series represents the next generation of crane-dedicated variable frequency drives, building upon the success of the CS700 platform with enhanced control algorithms, expanded safety monitoring capabilities, and broader communication integration options. Designed for the full spectrum of crane applications including hoisting, traversing (trolley), and slewing (gantry) mechanisms, the CS710 covers a power range from 0.4 kW to 450 kW, making it suitable for both light-duty workshop cranes and heavy-duty port container handling equipment.

Product Positioning and Evolution

The CS710 has undergone continuous development from 2015 through 2021, progressing through firmware versions A00 to A10. Each iteration has refined the crane control algorithms and expanded the drive’s functional capabilities. The series supports both open-loop vector control (sensorless) and closed-loop vector control (with encoder feedback), allowing the same drive platform to serve applications ranging from simple trolley travel to precision hoisting with position feedback.

A key differentiator of the CS710 from general-purpose drives is its support for crane-specific technology cards. These optional expansion cards implement advanced crane functions including anti-sway control and grab bucket operation mode, which are not available through the base drive firmware. The technology cards communicate with the drive through a dedicated internal bus, providing real-time torque and speed adjustments that respond to the dynamic conditions encountered during crane operation.

Enhanced Crane Control Algorithms

Open-Loop Vector Control (b1.00=0)

The CS710’s sensorless vector control mode provides high-performance speed and torque control without requiring an encoder. This mode is suitable for trolley travel, gantry movement, and many hoisting applications where the cost and complexity of encoder installation are not justified. The drive estimates rotor flux position from stator current measurements and motor parameter data, achieving speed control accuracy of plus or minus 0.1% and torque response under 15 ms.

Motor parameter auto-tuning is essential before commissioning in this mode. The drive performs a dynamic tuning sequence that applies test signals to the motor to measure stator resistance, rotor resistance, leakage inductance, and mutual inductance. For accurate results, the motor should be unloaded during dynamic tuning. If the motor cannot be uncoupled from the mechanism, static tuning can be performed, though the resulting parameter accuracy may be reduced.

Closed-Loop Vector Control (b1.00=1)

For applications requiring the highest levels of speed accuracy and torque control at near-zero speeds, the CS710 supports closed-loop vector control with encoder feedback. This mode requires proper configuration of encoder line count, encoder type, and signal direction parameters. After configuration, motor parameter auto-tuning must be performed to complete the motor model.

Closed-loop control is recommended for main hoisting applications where precise load positioning and controlled load lowering at very low speeds are critical safety requirements. The encoder feedback eliminates the speed estimation error inherent in sensorless control, particularly at frequencies below 1 Hz where sensorless algorithms struggle to maintain stable torque output.

V/F Control (b1.00=2)

V/F control mode is available for applications where motor parameter sensitivity is not critical, such as multi-motor drive systems or retrofit applications where motor nameplate data is incomplete. In V/F mode, the drive maintains a constant voltage-to-frequency ratio and does not require motor parameter auto-tuning. This mode is also useful for commissioning new systems before switching to vector control, as it provides basic motor operation without the risk of parameter tuning errors.

Dual-Zone Speed Loop PI Control

The CS710 implements a sophisticated dual-zone speed loop PI controller through the F1 group parameters. Two independent sets of proportional gain and integral time constants are configured, with automatic switching based on operating frequency:

• Zone 1 (below switching frequency F1.02, default 5.00 Hz): Uses F1.00 (proportional gain, default 60) and F1.01 (integral time, default 0.50s)
• Transition zone (between F1.02 and F1.05): Linearly interpolates between Zone 1 and Zone 2 parameters
• Zone 2 (above switching frequency F1.05, default 10.00 Hz): Uses F1.03 (proportional gain, default 20) and F1.04 (integral time, default 1.00s)

This dual-zone approach recognizes that crane mechanisms have different dynamic characteristics at low and high speeds. At low speeds, higher proportional gain and shorter integral time provide the fast torque response needed for precise load handling. At high speeds, reduced gains prevent oscillation and ensure smooth travel. The speed loop filter time constant (F1.06, default 0.070s) provides additional damping for the torque command output.

Current Loop PI Control

The inner current loop uses F1.08 (excitation proportional gain, default 2000), F1.09 (excitation integral gain, default 1300), F1.10 (torque proportional gain, default 2000), and F1.11 (torque integral gain, default 1300). These parameters are automatically obtained during motor parameter auto-tuning and generally do not require manual adjustment. However, if current oscillation occurs, manually reducing the PI gains can stabilize the system.

Operation Panel and Parameter Groups

The CS710 uses the MF.K series LED operation panel, featuring a five-digit seven-segment display, RUN and STOP/RESET keys, navigation keys, and unit indicator LEDs. The panel provides real-time monitoring of operating frequency, output current, output voltage, DC bus voltage, motor speed, and other parameters.

Parameter Menu Structure

The CS710 parameter system follows the same three-tier architecture as the CS200, with the following groupings:

• Level 1 (b0, b1, b3 groups): Basic drive configuration including control mode, motor parameters, and digital input terminal functions
• Level 2 (bE, bC, bF groups): Crane-specific application parameters including protection settings, brake control, communication configuration, and fault level assignment
• Level 3 (F0-F3, FF groups): Advanced engineering parameters for performance tuning

Parameter bF.00 protects Level 2 access with a password, and FF.00 protects Level 3. The Level 3 factory reset function (FF.10) preserves F0.00 through F0.04, F0.16, F2.01, F2.11, and FF.00 when restoring Level 3 defaults, ensuring that critical system configuration is not lost during a reset.

V/F Control Parameters (F2 Group)

For V/F control mode, the F2 group provides tuning parameters:

• F2.01 (Torque boost): Compensates for low-frequency torque reduction by increasing output voltage at low speeds. Setting to 0.0% enables automatic torque boost based on motor stator resistance. Excessive torque boost causes motor overheating and drive overcurrent.
• F2.02 (Torque boost cutoff frequency): Defines the frequency above which torque boost is disabled (default 50.00 Hz)
• F2.09 (V/F slip compensation gain): Compensates for motor speed reduction under load. 100% compensation fully offsets rated slip at rated load. Only effective for asynchronous motors.
• F2.10 (V/F overexcitation gain): Suppresses DC bus voltage rise during deceleration by increasing motor excitation, reducing the need for braking resistors. Set to 0 when braking resistors are installed or for low-inertia applications.
• F2.11 (Oscillation suppression gain): Damps motor oscillation in V/F mode. Increase in increments of 10 when oscillation is observed. Set to 0 when no oscillation is present.

Control Optimization Parameters (F3 Group)

The F3 group contains advanced parameters that influence drive performance:

• F3.00 (DPWM switching frequency): Sets the frequency threshold between 7-segment continuous PWM and 5-segment discontinuous PWM. Below the threshold, 7-segment modulation provides lower current ripple but higher switching losses; above it, 5-segment modulation reduces losses but increases ripple (default 12.00 Hz)
• F3.01 (PWM modulation mode): 0=asynchronous (default), 1=synchronous. Synchronous modulation only activates above 85 Hz output frequency and maintains a constant carrier ratio.
• F3.02 (Dead time compensation mode): 0=no compensation, 1=mode 1 (default), 2=mode 2 (recommended for high-power drives)
• F3.03 (Random PWM depth): 0=disabled (default), 1-10=random depth. Random PWM softens motor acoustic noise by spreading the switching frequency spectrum.
• F3.04 (Fast current limit enable): 0=disabled, 1=enabled (default). Rapidly limits output current to prevent overcurrent trips, but prolonged operation in current limit triggers fault code 40 (cycle-by-cycle current limit)
• F3.06 (Undervoltage threshold): Sets the bus voltage level below which undervoltage fault 09 is triggered (350V for 380-480V models, 200V for 200-240V models)

Safety Monitoring Functions

Five-Level Fault Classification

The CS710 implements a sophisticated five-level fault classification system that tailors the drive’s response based on fault severity:

Level	Drive Response	Output Functions	Example Faults
Level 1 (most severe)	Free stop (coast to stop)	Brake control output inactive; fault stop output active	Faults 1-40 (drive performance faults); cannot be reclassified
Level 2	Quick stop (rapid deceleration)	Fault alarm output active	User-configurable faults 41-65
Level 3	Deceleration stop (normal decel ramp)	Fault alarm output active	User-configurable faults 41-65
Level 4	Operation continues	Fault notification output active	User-configurable faults 41-65
Level 5 (least severe)	Operation continues	No output change	Minor warnings

Faults 1 through 40 are drive performance faults (overcurrent, overvoltage, overload, etc.) and are permanently assigned to Level 1 as they indicate conditions that could damage the drive or create unsafe operating conditions. Faults 41 through 65 are function-level faults whose severity level can be adjusted by the user through parameters bF.10 through bF.14, allowing application engineers to customize the fault response to match the specific crane safety requirements.

Brake Failure Protection (Er453)

A critical safety feature unique to crane applications is the brake failure protection function. When the drive commands a stop and the brake is applied, the CS710 continues monitoring encoder feedback (in FVC mode, b1.00=1). If the encoder pulse count continues to accumulate after the brake is applied, the drive detects that the brake has failed to hold the load and automatically outputs a 0 Hz holding torque to prevent the load from dropping. The brake failure detection sensitivity is configured through parameter bc.00; setting bc.00 to 0 disables this function.

Brake Feedback Monitoring

The CS710 monitors two distinct brake feedback signals through dedicated DI input functions:

• Input function 11 (brake release feedback): Verifies that the brake has actually released before the drive applies motor torque. Fault Er-star-41 (brake release fault) triggers if the release feedback signal does not match the drive command.
• Input function 12 (brake apply feedback): Verifies that the brake has engaged after the drive stops. Fault Er-star-42 (brake apply fault) triggers if the apply feedback is incorrect.

Other Crane-Specific Safety Functions

• Axial-cooled motor low-speed timeout (Er-star-43): Protects motors that rely on shaft-mounted fans for cooling from overheating during prolonged low-speed operation. Parameters b0.00 and b0.01 set the low-speed duration limit.
• Simultaneous forward/reverse command (Er-star-44): Detects when both forward and reverse run commands are active simultaneously, which could indicate a control circuit fault
• Joystick not at zero (Er-star-45): Prevents drive startup if a run command or frequency reference is active at power-up, ensuring the operator returns the joystick to the neutral position before starting
• Frequency direction anomaly (Er137): Detects when the motor feedback frequency direction opposes the commanded frequency direction, indicating possible overload or parameter mismatch. Adjust bc.02 to modify detection sensitivity.
• Frequency tracking anomaly (Er138): Triggers when the tracking error between commanded and feedback frequency exceeds the threshold. Adjust bc.03 and bc.04 to modify detection parameters.

Communication and PLC Integration

The CS710 supports comprehensive communication options for integration with crane control systems and upper-level monitoring platforms:

• Modbus RTU: Standard RS485 serial communication, with a complete Modbus protocol specification in the manual appendix. The control command address 2000H accepts command values including run, stop, and fault reset (writing 7 to 2000H triggers reset).
• CANlink: Inovance proprietary CAN protocol for drive-to-drive communication in multi-axis crane systems
• PROFINET: Via optional MD500-PN1 expansion card for Siemens PLC integration
• PROFIBUS DP: Via optional MD38DP2 expansion card
• EtherCAT: Via optional MD38TX1 expansion card for Beckhoff and other EtherCAT masters

Communication fault Er-star-48 triggers when the master device goes offline or communication parameters (bd group) are incorrectly configured. CANlink communication fault Er-star-47 indicates a problem with the CANlink expansion card or inter-card wiring.

Technology Card Integration

The CS710 supports crane technology cards (CS70CF series) that implement advanced functions including anti-sway control and grab bucket operation. When a technology card is installed, communication between the drive and the card is monitored, and fault Er-star-46 (technology card communication fault) triggers if the inter-card communication fails. Parameter bF.18 must be correctly configured to match the installed technology card type.

Expansion Cards

The CS710 supports a comprehensive range of expansion cards:

• MD38IO1, MD38IO2, MD38IO3: Digital and analog I/O expansion cards with varying channel counts
• CS700IO1: Crane-specific I/O expansion card with dedicated safety relay outputs
• CS700RC2: Crane-specific relay expansion card
• MD38CAN2: Second CAN channel expansion card for dual-bus applications
• MD38TX1: EtherCAT communication expansion card
• MD38DP2: PROFIBUS DP communication expansion card
• MD500-PN1: PROFINET communication expansion card
• MD38PGMD: Encoder interface card for multi-encoder applications
• MD38PG4: Four-channel encoder interface card

System Configuration and Peripheral Selection

The CS710 system architecture includes several peripheral components essential for crane applications:

• Circuit breaker: Provides short-circuit protection and serves as the main disconnect
• Fuse: Protects semiconductor devices from short-circuit currents
• Electromagnetic contactor: Controls drive power application; avoid frequent on/off cycling (minimum one-hour interval between operations)
• Input reactor: Improves power factor and suppresses input harmonics; recommended for all installations
• EMC filter: Reduces conducted and radiated emissions; essential for meeting CE requirements
• DC reactor: Standard on models 30 kW and above; optional on 18.5-22 kW models; improves power factor and thermal stability
• Braking resistor: Required on models 75 kW and below for dissipating regenerative energy during lowering operations
• External braking unit (MDBUN): Required on models above 75 kW for connecting external braking resistors

The braking resistor selection must account for the crane’s duty cycle and the maximum regenerative power during load lowering. Insufficient braking capacity leads to overvoltage faults (Er105, Er106, Er107) and potential drive damage.

Fault Codes and Troubleshooting

The CS710 provides comprehensive fault diagnostics with detailed cause analysis and corrective actions:

Fault Code	Fault Name	Primary Causes	Corrective Actions
Er102	Acceleration overcurrent	Output short circuit; motor not tuned; acceleration too short; voltage too low; starting rotating motor; sudden load applied; undersized drive	Check output wiring; perform auto-tuning; increase accel time; verify voltage; use speed tracking start; remove sudden loads; use larger drive
Er103	Deceleration overcurrent	Output short circuit; motor not tuned; deceleration too short; no braking resistor; brake circuit shorted	Check wiring; perform auto-tuning; increase decel time; install braking unit and resistor; check brake circuit
Er105/106/107	Overvoltage (accel/decel/constant speed)	Input voltage too high; external driving force; insufficient braking capacity	Adjust voltage; remove external force or add braking resistor; verify braking unit operation
Er109	Undervoltage	Power interruption; input voltage out of range; bus voltage abnormal; rectifier or buffer resistor fault; drive board or control board fault	Reset fault; adjust voltage; seek technical support for hardware faults
Er110	Drive overload	Excessive load or motor stall; undersized drive	Reduce load and check mechanism; use larger drive
Er111	Motor overload	Motor protection parameter bE.01 set incorrectly; excessive load or stall; undersized drive	Correct bE.01 setting; reduce load; use larger drive
Er114	Power module overheat	High ambient temperature; blocked airflow; fan failure; thermal sensor failure; IGBT failure	Reduce ambient temperature; clean air path; replace fan; replace thermal sensor; replace IGBT module
Er115	Built-in braking unit overload	Braking resistor undersized; resistor shorted; braking unit damaged; excessive regenerative energy	Select larger resistor; check wiring; seek technical support; reduce regenerative load
Er117	Contactor fault	Drive board or power supply fault; contactor failure	Replace drive board or power supply; replace contactor
Er120	Encoder fault	Encoder type mismatch; wiring error; encoder damaged; PG card fault	Verify encoder type setting; check wiring; replace encoder; replace PG card
Er453	Brake failure protection	Brake unable to hold load; detected via encoder feedback in FVC mode	Inspect brake for looseness; increase brake torque; adjust bc.00 sensitivity; set bc.00 to 0 to disable

Commissioning Troubleshooting Guide

The CS710 manual provides structured troubleshooting tables for each control mode:

Open-loop vector control (b1.00=0) issues:

• Startup overcurrent or overload: Verify motor parameters A0.01 through A0.05 match the nameplate; perform motor auto-tuning (b0.04)
• Below 5 Hz poor torque or speed response: Increase F1.00 in increments of 10; decrease F1.01 in increments of 0.05s
• Above 5 Hz poor response: Adjust F1.03 in increments of 10; decrease F1.04 in increments of 0.05s
• Excessive speed deviation: Increase slip compensation b1.01 in increments of 10%
• Speed oscillation: Increase F1.06 speed loop filter time in increments of 0.001s
• Insufficient torque: Check if torque limit (b1.04, b1.05) is restricting output; increase torque limit or torque command

V/F control (b1.00=2) issues:

• Motor oscillation during operation: Increase F2.11 oscillation suppression gain in increments of 10 (maximum 100)
• Overcurrent on large-power startup: Decrease F2.01 torque boost in increments of 0.5%
• Excessive running current: Verify A0.02 rated voltage and A0.04 rated frequency; decrease F2.01 torque boost

The CS710 series represents a mature, feature-rich platform for crane drive applications, combining proven vector control algorithms with comprehensive safety monitoring and flexible communication options. Its five-level fault classification system and dedicated crane safety functions make it particularly well-suited for safety-critical lifting operations where regulatory compliance and operational reliability are paramount.