SK600 Series Universal Variable Frequency Drive User Manual

Preface

First of all, thank you for purchasing SK600 series frequency converters. SK600 series frequency converters are high-performance general-purpose current vector frequency converters, which can realize asynchronous motor and permanent magnet synchronous motor control, with user programmable functions, background monitoring software, communication bus functions, supporting multiple PG cards, etc., with powerful functions. It can be used for driving textile, papermaking, wire drawing, machine tools, packaging, food, fans, pumps and various automated production equipment.

This manual introduces the functional characteristics and usage methods of SK600 series frequency converters, including product selection, parameter setting, operation debugging, maintenance inspection, etc. Please be sure to read this manual carefully before use. Equipment supporting manufacturers please send this manual to end users with the equipment for subsequent reference.

Product Introduction

SK600 frequency converters have obvious improvements in the following aspects:

1. Rich voltage levels: Support six voltage levels: single-phase 220V, three-phase 220V, three-phase 380V, three-phase 480V, three-phase 690V, three-phase 1140V.
2. Rich motor type support: Support vector control of three-phase AC asynchronous motors and three-phase AC permanent magnet synchronous motors.
3. Rich control methods: In addition to speed sensor vector control, sensorless vector control, V/F control, it also supports V/F separation control.
4. Rich field buses: Support four buses: Modbus - RTU, Profibus - DP, CANlink, CANopen.
5. Rich encoder types: Support differential encoders, open collector encoders, resolvers, UVW encoders, etc.
6. Brand new sensorless vector control algorithm: Brand new SVC (Sensorless Vector Control) brings better low-speed stability, stronger low-frequency load capacity, and supports torque control of SVC.
7. Support user programmable: Through PC60PC1 user programmable card, users can realize secondary development functions, and can write programs in ladder diagram and other ways.
8. Powerful background software: The background software can realize functions such as uploading, downloading, and real-time oscilloscope of frequency converter parameters.
9. More abundant functions:

Precautions

• To illustrate the details of the product, the diagrams in this manual are sometimes in a state where the outer cover or safety cover is removed. When using this product, please be sure to install the shell or cover according to regulations, and operate according to the content of the manual.
• The illustrations in this manual are for illustration only and may differ from the product you ordered.
• Our company is committed to continuous improvement of products, product functions will be continuously upgraded, and the information provided is subject to change without notice.
• If you have any problems during use, please contact our regional agents or directly contact our customer service center.

Unpacking Inspection

When unpacking, please carefully confirm:

• Whether the model and rated value of the inverter on the nameplate are consistent with your order. The box contains your ordered machine, product certificate, user operation manual and warranty card.
• Whether the product is damaged during transportation; If you find any missing or damaged items, please contact our company or your supplier immediately for solution.

First Use

For users who use this product for the first time, they should read this manual carefully. If you have any doubts about some functions and performance, please consult our technical support personnel for help, which is beneficial to the correct use of this product.

Connection with Peripheral Equipment

Please use three-phase AC power within the allowed specifications of the frequency converter. Since a large inrush current will flow into the frequency converter when the power is turned on, attention should be paid to the selection of the circuit breaker. To ensure safety, do not frequently use electromagnetic contactors to start and stop the frequency converter, which will reduce the service life of the frequency converter.

1. Safety Information and Precautions

1.1 Safety Definitions

In this manual, safety precautions are divided into the following two categories:

Please read this chapter carefully when installing, debugging and maintaining this system, and be sure to follow the safety precautions required in this chapter. Any injury and loss caused by illegal operation has nothing to do with our company.

1.2 Safety Matters

1.3 Precautions

1. Motor insulation check: The motor should be checked for insulation before first use, reuse after long-term storage and regular inspection to prevent damage to the frequency converter due to insulation failure of the motor windings. During insulation check, be sure to separate the motor connection from the frequency converter, it is recommended to use a 500V voltage type megohmmeter, and ensure that the measured insulation resistance is not less than 5MΩ.
2. Motor thermal protection: If the selected motor does not match the rated capacity of the frequency converter, especially when the rated power of the frequency converter is greater than the rated power of the motor, be sure to adjust the motor protection related parameters in the frequency converter or add a thermal relay in front of the motor to protect the motor.
3. Operation above power frequency: This frequency converter can provide 0Hz - 500Hz output frequency. If the customer needs to run above 50Hz, please consider the bearing capacity of the mechanical device.
4. Vibration of mechanical devices: The frequency converter may encounter the mechanical resonance point of the load device at some output frequencies, which can be avoided by setting the jump frequency parameters in the frequency converter.
5. About motor heating and noise: Because the output voltage of the frequency converter is PWM wave, which contains certain harmonics, the temperature rise, noise and vibration of the motor will be slightly increased compared with power frequency operation.
6. When there are voltage-sensitive devices or capacitors to improve power factor on the output side: The output of the frequency converter is PWM wave, and if capacitors to improve power factor or lightning protection varistors are installed on the output side, it is easy to cause instantaneous overcurrent of the frequency converter or even damage the frequency converter. Please do not use.
7. Contactor and other switching devices used at input and output ends of frequency converter: If a contactor is installed between the power supply and the input end of the frequency converter, it is not allowed to use this contactor to control the start and stop of the frequency converter. If it is necessary to use this contactor to control the start and stop of the frequency converter, the interval should not be less than one hour. Frequent charging and discharging will reduce the service life of the capacitor in the frequency converter. If there are contactors and other switching devices between the output end and the motor, ensure that the frequency converter is switched on and off when there is no output, otherwise it is easy to cause damage to the modules in the frequency converter.
8. Lightning shock protection: This series of frequency converters is equipped with lightning overcurrent protection devices, which have a certain self-protection ability against induced lightning. For areas with frequent lightning, customers should also install protection at the front end of the frequency converter.
9. Altitude and derating use: In areas with altitude above 1000m, due to the thin air, the heat dissipation effect of the frequency converter becomes worse, so it is necessary to derate use. Please consult our company for technical advice in this case.
10. Some special uses: If the customer needs to use methods other than the recommended wiring diagram provided in this manual, such as common DC bus, please consult our company.
11. Attention when scrapping frequency converters: Electrolytic capacitors in the main circuit and electrolytic capacitors on printed circuit boards may explode when incinerated. Plastic parts will produce toxic gases when incinerated. Please handle as industrial waste.
12. About suitable motors:
    • Standard suitable motors are four-pole squirrel cage asynchronous induction motors or permanent magnet synchronous motors. If it is not the above motor, please select the frequency converter according to the rated current of the motor.
    • The cooling fan of non-frequency conversion motor is coaxially connected with the rotor shaft, and the cooling effect of the fan decreases when the speed decreases. Therefore, forced exhaust fans should be added or replaced with frequency conversion motors in situations where the motor overheats;
    • The frequency converter has built-in standard parameters for suitable motors. It is necessary to identify motor parameters or modify default values according to actual conditions to better match actual values, otherwise it will affect operation effect and protection performance;
    • Because short circuit inside the cable or motor will cause frequency converter alarm, and even explosion. Therefore, please first test the insulation short circuit of the initially installed motor and cable, and also conduct this test frequently in daily maintenance. Note that when doing this test, be sure to disconnect the frequency converter from all parts being tested.

2. Inverter Model and Technical Parameters

2.1 SK600 Series Inverter Model and Technical Parameters

2.2 Technical Specifications

2.3 SK600 Inverter Appearance and Installation Hole Dimension (mm)

2.4 SK600 Inverter External Keyboard Opening Dimension

3. Daily Maintenance and Maintenance of Inverters

3.1 Daily Maintenance

Due to the influence of ambient temperature, humidity, dust and vibration, the internal components of the frequency converter will age, leading to potential failures of the frequency converter or reducing its service life. Therefore, it is necessary to carry out daily and regular maintenance and maintenance of the frequency converter.

1. Daily inspection items:
   • Whether the sound of the motor changes abnormally during operation.
   • Whether the motor vibrates during operation.
   • Whether the installation environment of the frequency converter changes.
   • Whether the cooling fan of the frequency converter works normally.
   • Whether the frequency converter is overheated.
2. Daily cleaning:
   • The frequency converter should always be kept clean.
   • Effectively remove dust on the surface of the frequency converter to prevent dust from entering the inside of the frequency converter, especially metal dust.
   • Effectively remove oil from the cooling fan of the frequency converter.

3.2 Regular Inspection

Please regularly check places that are difficult to check during operation.

1. Regular inspection items:
   • Check the air duct and clean it regularly.
   • Check whether the screws are loose.
   • Check whether the frequency converter is corroded.
   • Check whether the wiring terminals have arc marks.
   • Main circuit insulation test.
2. Reminder: When measuring the motor insulation resistance with a megohmmeter (please use a DC 500V megohmmeter), the main circuit line should be disconnected from the frequency converter. Do not test the insulation of the control circuit with an insulation resistance meter, and no high voltage test is required (completed at the factory).

3.3 Replacement of Vulnerable Parts of Inverters

The vulnerable parts of the frequency converter are mainly cooling fans and filtering electrolytic capacitors, and their service life is closely related to the use environment and maintenance conditions. The general service life is:

Users can determine the replacement period according to the running time.

1. Cooling fan:
   • Possible damage reasons: bearing wear, blade aging.
   • Judgment standard: whether there are cracks in the fan blades, whether there is abnormal vibration sound when starting.
2. Filter electrolytic capacitor:
   • Possible damage reasons: poor input power quality, high ambient temperature, frequent load jumps, electrolyte aging.
   • Judgment standard: whether there is liquid leakage, whether the safety valve has protruded, measurement of electrostatic capacitance, measurement of insulation resistance.

3.4 Storage of Inverters

After users purchase frequency converters, attention must be paid to the following points for temporary storage and long-term storage:

1. When storing, try to put it into our company’s packaging box according to the original packaging.
2. Long-term storage will lead to deterioration of electrolytic capacitors. It must be ensured that the power is turned on once within 2 years, and the power-on time is at least 5 hours. The input voltage must be slowly increased to the rated value with a voltage regulator.

3.5 Warranty Instructions for Inverters

1. Free warranty only refers to the frequency converter itself. Under normal use, if failure or damage occurs, our company is responsible for 20 months warranty (from the date of manufacture, subject to the barcode on the machine), more than 20 months, reasonable maintenance fees will be charged.
2. Within 20 months, if the following situations occur, a certain maintenance fee should be charged:
   • Damage to the machine caused by the user’s failure to follow the provisions in the user manual.
   • Damage caused by fire, flood, abnormal voltage, etc.
   • Damage caused by using the frequency converter for non-normal functions.
3. The service fee is calculated according to the unified standard of the manufacturer. If there is a contract, it will be handled according to the principle of contract priority.

4. Selection Guide for Inverter Brake Components

4.1 Selection Guide for Brake Components

The following selection table is a guide data, users can choose different resistance values and power according to the actual situation (but the resistance value must not be less than the recommended value in the table, the power can be large). The selection of brake resistance needs to be determined according to the power generated by the motor in the actual application system, which is related to system inertia, deceleration time, energy of potential energy load, etc., and needs to be selected by customers according to the actual situation. The greater the inertia of the system, the shorter the required deceleration time, and the more frequent the braking, the greater the power and smaller the resistance value of the brake resistance need to be selected.

1. Selection of resistance value: During braking, almost all the regenerative energy of the motor is consumed in the brake resistance. According to the formula: $U*U/R = Pb$, where $U$ is the brake voltage for stable braking of the system (different systems are different, generally 700V for 380VAC system), and $Pb$ is the brake power.
2. Selection of brake resistance power: In theory, the power of the brake resistance is consistent with the brake power, but considering derating to 70%. According to the formula: $0.7Pr = PbD$, $Pr$ is the power of the resistance, $D$ is the brake frequency (the proportion of the regenerative process in the entire working process). The brake frequency of elevators, unwinding and winding is 20% - 30%, that of centrifuges is 50% - 60%, that of accidental brake loads is 5%, and generally 10% is taken.

4.2 Inverter Brake Component Selection Table

Note: ×2 means two brake units with their respective brake resistors are used in parallel, and ×3 has the same meaning as ×2.

5. Mechanical and Electrical Installation of Inverters

5.1 Single-phase Inverter Main Circuit Terminal Description

5.2 Three-phase Inverter Main Circuit Terminal Description

5.3 Wiring Precautions

1. Input power L1, L2 or R, S, T: The input side wiring of the frequency converter has no phase sequence requirements.
2. DC bus (+), (-)
   • Note that there is still residual voltage on the DC bus (+), (-) terminals just after power failure. You must wait for the CHARGE light to go out and confirm that the power is off for 10 minutes before wiring, otherwise there is a danger of electric shock.
   • When selecting external brake components for 37kW and above (18.5kW and above for 220V), note that the (+) and (-) polarities cannot be reversed, otherwise it will cause damage to the frequency converter or even fire.
   • The wiring length of the brake unit should not exceed 10m, and twisted pair or tightly parallel double wires should be used for wiring.
   • The brake resistor cannot be directly connected to the DC bus, which may cause damage to the frequency converter or even fire.
3. Brake resistor connection terminals (+), PB
   • The brake resistor connection terminals are only valid for models with built-in brake units confirmed below 30kW (below 15kW for 220V).
   • The selection of brake resistor refers to the recommended value and the wiring distance should be less than 5m, otherwise it may cause damage to the frequency converter.
4. External reactor connection terminals P, (+): For frequency converters with power above 75kW (above 37KW for 220V), the reactor is external. When assembling, remove the connection piece between the P and (+) terminals, and connect the reactor between the two terminals.
5. Inverter output side U, V, W
   • Capacitors or surge absorbers cannot be connected to the output side of the frequency converter, otherwise it will cause frequent protection of the frequency converter or even damage.
   • When the motor cable is too long, due to the influence of distributed capacitance, it is easy to produce electrical resonance, which will cause damage to the motor insulation or produce large leakage current to make the frequency converter overcurrent protection. When the motor cable length is greater than 100m, an AC output reactor must be installed.
6. Grounding terminal PE
   • The terminal must be reliably grounded, and the grounding wire resistance must be less than 0.1Ω, otherwise it will cause abnormal operation or damage to the equipment.
   • The grounding terminal and the power zero line N terminal cannot be shared.

6. Inverter Control Circuit Wiring Method

6.1 Control Circuit Wiring Diagram

6.2 Control Terminal Description

The control circuit terminal layout is as follows:

485 + 、+10V、AI1、AI2、DI1、DI2、DI3、DI4、DI5、COM、485 - 、GND、GND、AO1、CME、COM、D01、FM、 + 24V、OP、T/A、T/B、T/C.

Control terminal function description:

7. Introduction to Inverter Operation and Display Interface

7.1 Introduction to Operation and Display Interface

Using the operation panel, you can modify the functional parameters of the frequency converter, monitor the working status of the frequency converter, and control the operation of the frequency converter (start, stop), etc. Its appearance and functional areas are shown in the following figure:

Command source indicator light, unit indicator light, RENIND LV, data display area, potentiometer adjustment key, programming key (PRG), increment key, confirm key (ENTER), decrement key, run key, stop/reset key, multi-function selection key, shift key.

1. Function indicator description:
   • RUN: When the light is off, it means the frequency converter is in stop state; when the light is on, it means the frequency converter is in running state.
   • LOCAL/REMOT: Keyboard operation, terminal operation and remote operation (communication control) indicator lights:

- FWD/REV: Forward/reverse indicator, the light is on when in forward rotation state.
- TUNE/TC: Tuning/torque control/fault indicator, the light is on when in torque control mode, slow flashing when in tuning state, fast flashing when in fault state.

2. Unit indicator lights: Hz (frequency unit), A (current unit), V (voltage unit), RPM(Hz + A) (speed unit), % (A + V) (percentage).
3. Digital display area: 5-digit LED display, can display set frequency, output frequency, various monitoring data and alarm codes, etc.
4. Keyboard button description table:

   Button	Name	Function
   PRG	Programming key	Enter or exit first-level menu
   ENTER	Confirm key	Enter menu screen level by level, confirm parameter setting
   △	Increment key	Increment of data or function code
   ▽	Decrement key	Decrement of data or function code
   ▽	Shift key	In stop display interface and running display interface, you can cycle to select display parameters; when modifying parameters, you can select the modification bit of parameters
   RUN	Run key	Used for run operation in keyboard operation mode
   STOP/RES	Stop/reset	When in running state, press this key to stop running; when in fault alarm state, it can be used for reset operation, the characteristics of this key are restricted by function code P7 - 02
   MF.K	Multi-function selection key	Switch selection according to P7 - 01 function
   QUICK	Menu mode selection key	Switch different menu modes according to the value in PP - 03 (default is one menu mode)

8. Basic Function Parameter Table of Inverter

Symbol Description

When PP-00 is set to a non-zero value, that is, a parameter protection password is set. In the function parameter mode and user change parameter mode, the parameter menu must be entered after correct password input. To cancel the password, set PP-00 to 0.

The parameter menu in user customized parameter mode is not password protected.

Group P and Group A are basic function parameters, and Group U is monitoring function parameters. Symbol description in the function table is as follows:

P0 Basic Function Group

P1 First Motor Parameters

P2 Group First Motor Vector Control Parameters

P3 Group V/F Control Parameters

P4 Group Input Terminals

P5 Group Output Terminals

P6 Group Start/Stop Control

P7 Group Keyboard and Display

P8 Group Auxiliary Functions

P9 Group Fault and Protection

PA Group PID Functions

Pb Group Swing Frequency, Fixed Length and Counting

PC Group Multi-segment Commands, Simple PLC

Pd Group Communication Parameters

PE Group User Customized Function Codes

PP Group Function Code Management

A0 Group Torque Control Parameters

A1 Group Virtual IO

A5 Group Control Optimization Parameters

A6 Group AI Curve Setting

A7 Group | User Programmable Card

AC Group AIAO Calibration

b0 Group Intelligent Constant Pressure Water Supply Parameters

U0 Group Basic Monitoring Parameters

9. Inverter Fault Diagnosis and Countermeasures

9.1 Fault Alarm and Countermeasures

The SK600 series inverter has a total of 24 warning information and protection functions. Once a fault occurs, the protection function activates, the inverter stops output, the inverter fault relay contact acts, and the fault code is displayed on the inverter display panel. Before seeking service, users can check themselves according to the tips in this section, analyze the fault causes, and find solutions. If it is due to the reasons described in the dashed box, please seek service and contact the agent of the inverter you purchased or directly contact our company.
Among the 21 warning information, Err22 is a hardware overcurrent or overvoltage signal. In most cases, hardware overvoltage fault causes Err22 alarm.

9.2 Common Faults and Their Handling Methods

During the use of the inverter, you may encounter the following fault situations, please refer to the following methods for simple fault analysis:

10. RS-485 Communication Expansion Card (PC60TX1) Instructions

10.1 Overview

It is specially developed to provide 485 communication function for SK600 series inverter. It adopts isolation scheme, and its electrical parameters comply with international standards. Users can choose it according to their needs to realize remote serial port control of inverter operation and parameter setting. For details of the communication card, please refer to “SK600 Serial Communication Protocol”.

10.2 Control Terminal Function Description

Table 2-1 Inverter control terminal function description

10.3 Communication Data Address Definition

SK600 series inverter supports Modbus, CANopen, CANlink, Profibus-DP four communication protocols. User programmable card and point-to-point communication are derivatives of CANlink protocol. The upper computer can realize inverter control, monitoring and function parameter modification and viewing operations through these communication protocols.

SK600 communication data can be divided into function code data and non-function code data. The latter includes operation commands, operation status, operation parameters, alarm information, etc.

10.4 SK600 Function Code Data

Function code data is important setting parameters for the inverter. SK600 has P group and A group function parameters, and the parameter groups are as follows:

Function code data communication address definition is as follows:

1. When reading function code data for communication: For P0-PF, A0-AF group function code data, the high 16 bits of the communication address are directly the function group number, and the low 16 bits are directly the sequence number of the function code in the function group, for example: P0-16 function parameter, its communication address is P010H, where P0H represents P0 group function parameters, 10H represents the hexadecimal data format of sequence number 16 in the function group. AC-08 function parameter, its communication address is AC08, where ACH represents AC group function parameters, 08H represents the hexadecimal data format of sequence number 8 of the function code in the function group.
2. When writing function code data for communication: For P0-PF group function code data, the high 16 bits of the communication address are divided into 00-0F or P0-PF according to whether to write to EEPROM, and the low 16 bits are directly the sequence number of the function code in the function group, for example: Write function in parameter P0-16: When EEPROM writing is not required, its communication address is 0010H. When EEPROM writing is required, its communication address is P010H. For A0-AF group function code data, the high 16 bits of the communication address are divided into 10-4F or A0-AF according to whether EEPROM writing is required, and the low 16 bits are directly the sequence number of the function code in the function group, for example: Write function parameter AC-08: When EEPROM writing is not required, its communication address is 4C08H. When EEPROM writing is required, its communication address is AC08H.

10.5 SK600 Non-Function Code Data

1. Status data: Status data is divided into U group monitoring parameters, inverter fault description, and inverter operation status. U group parameter monitoring parameters: U group monitoring data description can be found in Chapter 5 and Chapter 6. Its address definition is as follows: U0-UF, its communication address high 16 bits are 70-7F, low 16 bits are the sequence number of the monitoring parameter in the group, for example: U0-11, its communication address is 700BH. Inverter fault description: When reading inverter faults through communication, the communication address is fixed at 8000H. The upper computer can obtain the current inverter fault code by reading the data at this address. The fault code description is defined in function code P9-14 in Chapter 5. Inverter operation status: When reading the inverter operation status through communication, the communication address is fixed at 3000H. The upper computer can obtain the current inverter operation status information by reading the data at this address, which is defined as follows:

   Inverter operation status communication address	Read status word definition
   3000H	1：Forward operation 2：Reverse operation 3：Stop

2. Control parameters: Control parameters are divided into control commands, digital output terminal control, analog output AO1 control, analog output AO2 control, and high-speed pulse (FMP) output control. Control commands: When P0-02 (command source) is selected as 2: Communication control, the upper computer can control the start and stop of the inverter through this communication address. The control command is defined as follows:

   Control command communication address	Command function
   2000H	1：Forward operation 2：Reverse operation 3：Forward jog 4：Reverse jog 5：Free stop 6：Deceleration stop 7：Fault reset

Communication set value: Communication set value is mainly used for the given data when the frequency source, torque upper limit source, VF separation voltage source, PID given source, PID feedback source, etc. in SK600 are selected as communication given. Its communication address is 1000H. When the upper computer sets the value of this communication address, its data range is -10000～10000, corresponding to the relative given value -100.00%-100.00%.

Digital output terminal control: When the digital output terminal function is selected as 20: Communication control, the upper computer can control the inverter digital output terminal through this communication address, which is defined as follows:

Analog output AO1, AO2, high-speed pulse output FMP control:

When the analog output AO1, AO2, and high-speed pulse output FMP output functions are selected as 12: Communication setting, the upper computer can control the inverter analog output and high-speed pulse output through this communication address, which is defined as follows:

Parameter initialization: This function is required when parameter initialization of the inverter needs to be implemented through the upper computer. If PP-00 (user password) is not 0, password verification is required first. After the verification is passed, the upper computer performs parameter initialization operation after 30 seconds. The communication address for communication password verification is 1F00H. The password verification can be completed by directly writing the correct user password into this address. The address for communication parameter initialization is 1F01H, and its data content is defined as follows:

11.Modbus Communication Protocol

SK600 series inverter provides RS485 communication interface and supports Modbus-RTU communication protocol. Users can implement centralized control through computers or PLC, set inverter operation commands, modify or read function code parameters, and read inverter working status and fault information through this communication protocol.

11.1 Protocol Content

This serial communication protocol defines the information content and usage format transmitted in serial communication. It includes: host polling (or broadcast) format; host coding method, including function code requiring action, transmission data and error check, etc. The slave response also adopts the same structure, including action confirmation, return data and error check, etc. If the slave makes an error when receiving information, or cannot complete the action requested by the host, it will organize a fault information as a response and feedback to the host.

Application method: The inverter is connected to a “single master multi-slave” PC/PLC control network with RS485 bus, as a communication slave.

Bus structure:

1. Topology structure: Single master multi-slave system. Each communication device in the network has a unique slave address, among which one device is used as the communication master (usually a PC upper computer, PLC, HMI, etc.), the master initiates communication, reads or writes parameters to the slave, and other devices are communication slaves, responding to the host’s inquiry or communication operation to the local machine. At the same time, only one device can send data, and other devices are in the receiving state. The setting range of slave address is 1-247, and 0 is the broadcast communication address. Slave addresses in the network must be unique.
2. Communication transmission mode: Asynchronous serial, half-duplex transmission mode. In the process of serial asynchronous communication, data is sent in the form of messages, sending one frame of data at a time. According to MODBUS-RTU protocol, when the idle time without data on the communication data line is greater than 3.5Byte transmission time, it indicates the start of a new communication frame. Master station sends 1 Slave station replies 1 Master station sends 2 Slave station replies 2 Greater than 3.5Byte data frame Greater than 3.5Byte data frame Transmission time Transmission time

The communication protocol built into SK600 series inverter is Modbus-RTU slave communication protocol, which can respond to the host’s “query/command”, or make corresponding actions according to the host’s “query/command”, and answer communication data. The host can be a personal computer (PC), industrial control equipment or programmable logic controller (PLC), etc. The host can communicate with a single slave machine alone, or broadcast information to all lower slave machines. For the host’s individual access “query/command”, the accessed slave machine must return a response frame frequency; for the broadcast information sent by the host, the slave machine does not need to feedback a response to the host.

Communication data structure: The Modbus protocol communication data format of SK600 series inverter is as follows. The inverter only supports reading or writing Word type parameters. The corresponding communication read operation command is Ox03; the write operation command is Ox06. Reading and writing of bytes or bits are not supported:

3.5Byte 1Byte 1Byte 2Byte 1Byte 2Byte Master station read command frame

In theory, the upper computer can read several consecutive function codes at a time (that is, n can be up to 12), but it should be noted that it cannot cross the last function code of this function code group, otherwise an error will be replied.

3.5Byte 1Byte 1Byte 1Byte (2n)Byte 2Byte Slave station read response frame 3.5Byte 1Byte 1Byte 2Byte 2Byte 2Byte Master station write command frame 3.5Byte 1Byte 1Byte 2Byte 2Byte 2Byte Slave station write response frame If the slave detects a communication frame error, or cannot read or write successfully for other reasons, it will reply with an error frame. 3.5Byte 1Byte 1Byte 1Byte 2Byte Slave station read response error frame Error type: 01：Command code error 02：Address error 3.5Byte 1Byte 1Byte 1Byte 2Byte 03：Data error 04：Command cannot be processed Slave station write response error frame

Data frame field description:

11.2 CMD Check Method:

Check method - CRC check method: CRC (Cyclical Redundancy Check) uses RTU frame format, and the message includes an error detection field based on CRC method. The CRC field detects the entire message content. The CRC field is two bytes, containing a 16-bit binary value. It is calculated by the transmission device and added to the message. The receiving device recalculates the CRC of the received message and compares it with the value in the received CRC field. If the two CRC values are not equal, it means there is an error in the transmission.

CRC is first stored as 0xFFFF, then a process is called to process the consecutive 8-bit bytes in the message with the current register value. Only the 8-bit data in each character is valid for CRC, and the start bit, stop bit and parity bit are invalid.

During the CRC generation process, each 8-bit character is individually XORed with the register content, and the result is shifted toward the least significant bit, with the most significant bit filled with 0. The LSB is extracted for detection. If the LSB is 1, the register is individually XORed with a preset value. If the LSB is 0, it is not performed. This process is repeated 8 times. After the last bit (8th bit) is completed, the next 8-bit byte is individually XORed with the current value of the register. The final value in the register is the CRC value after all bytes in the message are executed.

When CRC is added to the message, the low byte is added first, then the high byte. The simple CRC function is as follows:

unsigned int crc_chk_value（unsigned char *data_value,unsigned char length）{
    unsigned int crc_value=0xFFFF;
    int i;
    while（length--） {
        crc_value^=*data_value++;
        for（i=0;i<8;i++） {
            if（crc_value&0x0001）
            {
                crc_value = （crc_value >> 1）^0xa001;
            }
            else
            {
                crc_value=crc_value>>1;
            }
        }
    }
    return（crc_value）;
}

11.3 Communication Parameter Address Definition

1. Read/write function code parameters (some function codes cannot be changed and are only for manufacturer use or monitoring):
   • Function code parameter address indication rule: Parameter address indication rule based on function code group number and label:
     • High byte: P0-PF (P group), A0-AF (A group), 70-7F (U group)
     • Low byte: 00-FF
     • For example: If you want to range function code P3-12, the access address of the function code is expressed as 0×P30C;
   • Note:
     • PF group: Neither parameter can be read nor changed;
     • U group: Only readable, not changeable parameters.
     • Some parameters cannot be changed when the inverter is in running state; some parameters cannot be changed regardless of the state of the inverter; when changing function code parameters, pay attention to the range, unit, and related instructions of the parameters.
   • Function code group number Communication access address Communication modification RAM function code address:
     • P0～PE group: 0×F000～0×FEFF 0×0000～0×0EFF
     • A0～AC group: 0×A000～0×ACFF 0×4000～0×4CFF
     • U0 group: 0×7000～0×70FF
   • Note: Because frequent storage of EEPROM will reduce the service life of EEPROM, some function codes in communication mode do not need to be stored, as long as the value in RAM is changed.
     • If it is a P group parameter, to realize this function, just change the high bit F of the function code address to 0.
     • If it is an A group parameter, to realize this function, just change the high bit A of the function code address to 4.
     • The corresponding function code address is as follows:
       • High byte: 00-0F (P group), 40-4F (A group)
       • Low byte: 00-FF
       • For example:
         • Function code P3-12 is not stored in EEPROM, and the address is expressed as 030C;
         • Function code A0-05 is not stored in EEPROM, and the address is expressed as 4005;
     • This address representation can only be used for writing RAM, not for reading. When reading, it is an invalid address.
     • For all parameters, the command code 07H can also be used to realize this function.
2. Stop/run parameter part:

   Parameter address	Parameter description	Parameter address	Parameter description
   1000	*Communication set value (decimal) -10000-10000	1010	PID setting
   1001	Running frequency	1011	PID feedback
   1002	Bus voltage	1012	PLC step
   1003	Output voltage	1013	PULSE input pulse frequency, unit 0.01kHz
   1004	Output current	1014	Feedback speed, unit 0.1Hz
   1005	Output power	1015	Remaining running time
   1006	Output torque	1016	AI1 voltage before correction
   1007	Running speed	1017	AI2 voltage before correction
   1008	DI input flag	1018	AI3 voltage before correction
   1009	DO output flag	1019	Linear speed
   100A	AI1 voltage	101A	Current power-on time
   100B	AI2 voltage	101B	Current running time
   100C	AI3 voltage	101C	PULSE input pulse frequency, unit 1Hz
   100D	Count value input	101D	Communication set value
   100E	Length value input	101E	Actual feedback speed
   100F	Load speed	101F	Main frequency X display
   1020	Auxiliary frequency Y display

   • Note:
     • The communication set value is a relative percentage, 10000 corresponds to 100.00%, and -10000 corresponds to -100.00%.- For data with frequency dimension, this percentage is the percentage relative to the maximum frequency (P0-10); for data with torque dimension, this percentage is P2-10, A2-48, A3-48, A4-48 (torque upper limit digital setting, corresponding to the first, second, third, and fourth motors respectively).
3. Control command input to inverter:(write only)

   Command word address	Command function
   2000	0001：Forward operation 0002：Reverse operation 0003：Forward jog 0004：Reverse jog 0005：Free stop 0006：Deceleration stop 0007：Fault reset

4. Read inverter status:(read only)

   Status word address	Status word function
   3000	0001：Forward operation 0002：Reverse operation 0003：Stop

5. Parameter lock password verification:(If the return is 8888H, it means the password verification is passed)

   Password address	Input password content
   1F00	*****

6. Digital output terminal control:(write only)

   Command address	Command content
   2001	BIT0：DO1 output control BIT1：DO2 output control BIT2：RELAY1 output control BIT3：RELAY2 output control BIT4：FMR output control BIT5：VDO1 BIT6：VDO2 BIT7：VDO3 BIT8：VDO4 BIT9：VDO5

7. Analog output AO1 control:(write only)

   Command address	Command content
   2002	0～7FFF represents 0％～100％

8. Analog output AO2 control:(write only)

   Command address	Command content
   2003	0～7FFF represents 0％～100％

9. Pulse (PULSE) output control:(write only)

   Command address	Command content
   2004	0～7FFF represents 0％～100％

10. Inverter fault description:

    Inverter fault address

    Inverter fault information

    8000

    0000：No fault 0001：Reserved 0002：Acceleration overcurrent 0003：Deceleration overcurrent 0004：Constant speed overcurrent 0005：Acceleration overvoltage 0006：Deceleration overvoltage 0007：Constant speed overvoltage 0008：Buffer resistor overload fault 0009：Undervoltage fault 000A：Inverter overload 000B：Motor overload 000C：Input phase loss 000D：Output phase loss 000E：Module overheating 000F：External fault 0010：Communication abnormality 0011：Contactor abnormality 0012：Current detection fault 0013：Motor tuning fault 0014：Encoder/PG card fault 0015：Parameter read/write abnormality 0016：Inverter hardware fault 0017：Motor ground short circuit fault 0018：Reserved 0019：Reserved 001A：Running time arrived 001B: User-defined fault 1 001C: User-defined fault 2 001D: Power-on time arrived 001E：Load loss 001F：Running PID feedback loss 0028：Fast current limiting timeout fault 0029：Motor switching fault during operation 002A: Speed deviation too large 002B：Motor overspeed 002D：Motor overheating 005A：Encoder line number setting error 005B：Encoder not connected 005C：Initial position error 005E：Speed feedback error

11. PD group communication parameter description:
    • Pd-00:
      • Baud rate: Factory value 6005
      • Setting range:
        • Units digit: MODUBS baud rate
          • 0：300BPS
          • 1：600BPS
          • 2：1200BPS
          • 3：2400BPS
          • 4：4800BPS
          • 5：9600BPS
          • 6：19200BPS
          • 7：38400BPS
          • 8：57600BPS
          • 9：115200BPS
      • This parameter is used to set the data transmission rate between the upper computer and the inverter. Note that the baud rate set by the upper computer and the inverter must be consistent, otherwise communication cannot be carried out. The larger the baud rate, the faster the communication speed.
    • Pd-01:
      • Data format: Factory value 0
      • Setting range:
        • 0：No parity: Data format <8,N,2>
        • 1：Even parity: Data format <8,E,1>
        • 2：Odd parity: Data format <8,O,1>
        • 3：No parity: Data format <8-N-1>
      • The data format set by the upper computer and the inverter must be consistent, otherwise communication cannot be carried out.
    • Pd-02:
      • Local address: Factory value 1
      • Setting range: 1-247, 0 is broadcast address
      • When the local address is set to 0, it is the broadcast address, realizing the upper computer broadcast function.
      • Local address is unique (except broadcast address), which is the basis for realizing point-to-point communication between upper computer and inverter.
    • Pd-03:
      • Response delay: Factory value 2ms
      • Setting range: 0-20ms
      • Response delay: Refers to the intermediate interval time from the end of inverter data reception to sending data to the upper computer. If the response delay is less than the system processing time, the response delay is based on the system processing time. If the response delay is longer than the system processing time, after the system processes the data, it needs to delay waiting until the response delay time is up before sending data to the upper computer.
    • Pd-04:
      • Communication timeout time: Factory value 0.0s
      • Setting range: 0.0s (invalid); 0.1-60.0s
      • When this function code is set to 0.0s, the communication timeout parameter is invalid.
      • When this function code is set to a valid value, if the interval between one communication and the next communication exceeds the communication timeout time, the system will report a communication fault error (Err16). Under normal circumstances, it is set to invalid. If in a continuous communication system, setting this parameter can monitor the communication status.
    • Pd-05:
      • Communication protocol selection: Factory value 0
      • Setting range: 0: Non-standard Modbus protocol; 1: Standard Modbus protocol
      • Pd-05=1: Select standard Modbus protocol.
      • Pd-05=0: When reading commands, the slave returns one more byte than the standard Modbus protocol, please refer to the “5 Communication data structure” section of this protocol for details.
    • Fd-06:
      • Communication read current resolution: Factory value 0
      • Setting range: 0：0.01A；1：0.1A
      • Used to determine the output unit of current value when reading output current through communication.

12. Get Installation Support

13. Related Documents