CFW700 - Modbus RTU
Contents
1. 22 7 FAULTS AND ALARMS RELATED THE MODBUS COMMUNICATION 24 128 228 SERIAL COMMUNICATION TIMEOUT 24 Ii 25 APPENDIX A ASCI 25 APPENDIX CRC CALCULATION USING 26 CFW700 4 mej About this Manual ABOUT THIS MANUAL This manual supplies the necessary information for the operation of the CFW700 frequency inverter using the RS232 and RS485 serial interfaces This manual must be used together with the CFW700 user manual ABBREVIATIONS AND DEFINITIONS ASCII American Standard Code for Information Interchange CRC Cycling Redundancy Check EIA Electronic Industries Alliance TIA Telecommunications Industry Association RTU Remote Terminal Unit NUMERICAL REPRESENTATION Decimal numbers are represented by means of digits without suffix Hexadecimal numbers are represented with the letter h after the number CFW700 5 Len Introduction to Serial Communicati2. Seaueddesaueressdewedsssoacerssteaeed 7 2 1 3 Terminating 7 2 1 4 Connection with the 5485 7 3 PROGRAMMING wascssinistsssiansnscntasasnnazsssnsnnasasnsubasanasasasnsasabasasanabanianeasainnpackbasansenaasannaannen 9 3 1 SYMBOLS FOR THE PROPERTIES 9 P0105 187 200 RAMP 5 9 P0220 LOCAL REMOTE SELECTION 5 1 111 1 2 1 1 1 9 P0221 SPEED REFERENCE SELECTION LOCAL SITUATION 222222 211 244 4 7 9 P0222 SPEED REFERENCE SELECTION REMOTE SITUATION 9 P0223 FORWARD REVERSE SELECTION LOCAL 5 9 P0224 RUN STOP SELECTION LOCAL 4244442 4 4 4 2 9 P0225 JOG SELECTION LOCAL
3. Dec Hex Chr Dec Hex Chr Dec Hex Chr Dec Hex Chr 0 00 NUL Null char 32 20 Sp 64 40 96 60 1 01 SOH Start of Header 33 21 65 41 87 61 a 2 02 STX Start of Text 34 22 66 42 B 98 62 b 3 03 ETX End of Text 35 23 67 43 99 63 4 04 EOT End of Transmission 36 24 5 68 44 D 100 64 d 5 05 ENQ Enquiry 37 25 5 69 45 E 101 65 e 6 06 ACK Acknowledgment 38 26 amp 7O 46 F 102 66 a 7 07 BEL Bell 39 27 d 47 G 103 67 g 8 08 BS Backspace 40 28 72 48 H 104 68 h 9 09 HT Horizontal Tab 41 29 72 49 I 105 69 3 0 0 LF Line Feed 42 2A j 74 4A J 106 6A j 1 OB VT Vertical Tab 43 2B 75 4B K 107 6B k 2 Form Feed 44 2 76 4 L 108 6 18 3 OD CR Carriage Return 45 2D 77 4D M 109 6D m 4 0 50 Shift Out 46 2E 18 4E N 110 6 n 5 OF 51 Shift 47 2 19 4 111 6F 10 DLE Data Link Escape 48 30 0 80 50 112 70 7 11 DEL Device Control 1 49 31 81 51 9 113 71 8 12 DEZ Device Control 2 50 32 2 82 52 R 114 72 E 9 13 DC3 Device Control 3 51 33 3 83 53 5 115 73 5 20 14 DC4 Device Control 4 52 34 4 84 54 T 116 74 21 15 Negative Acknowledgement 52 35 5 85 55 0 117 75 u 22 L6 SYN Synchronous Idle 54 36 6 86 56 118 76 23 17 End of Trans Block 55 37 7 87 57 W 119 77 24 18 Cancel 56 38 8 88 58 120 78 x 25 19 End of Medium 57 39 9 89 59 79 26 LA SUB Substitute
4. 11 P0681 MOTOR SPEED IN 13 54 43545554554545444544 5544345 54443545 5 12 P0682 SERIAL CONTROL 13 P0683 SERIAL SPEED 44424445444 444343424245544 414384524443445 444385444343545541534 13 P0695 DIGITAL OUTPUT 6 2 2 2 2 1 44 14 P0696 VALUE 1 FOR ANALOG 5 2 4 4 412 441 74 nnna na 15 P0697 VALUE 2 FOR ANALOG 5 2 2 2 2 2 4 4 44 444444044 4 2104 15 4 MODBUS 16 4 1 TRANSMISSION 16 4 2 MESSAGE STRUCTURE FOR 16 4 2 1 5 4442 448444 4444045144454445444444544 148445
5. 4 4 44444444444444444444 1 9 P0226 FORWARD REVERSE SELECTION REMOTE SITUATION 9 P0227 RUN STOP SELECTION REMOTE SITUATION 2 4444 9 P0228 JOG SELECTION REMOTE 4 2 1111 9 P0308 SERIAL 55 45 9 P0310 SERIAL BAUD 9 P0311 SERIAL INTERFACE BYTE CONFIGURATION 10 P0313 COMMUNICATION ERROR 1 1 1 02 44 441 4 10 P0314 SERIAL WATCHDOG 24445445 4 4443434345445 4445844244454444444343424445844 45458 424343484544438 11 P0316 SERIAL INTERFACE 5 5 11 P0680 STATUS caca
6. 13 bit reference 900 x 8192 1800 13 bit reference 4096 gt Value corresponding to 900 rpm in a 13 bit scale This parameter also accepts negative values to revert the motor speed direction The reference speed direction however depends also the control word 682 bit 2 setting Bit2 1 P0683 gt 0 reference for forward direction Bit2 1 and P0683 lt 0 reference for reverse direction Bit 2 0 and P0683 gt 0 reference for reverse direction Bit 2 0 and P0683 lt 0 reference for forward direction P0695 DIGITAL OUTPUT SETTING Range 0000h to 001Fh Default 0000h Properties Net Access groups via HMI NET Description It allows the control of the digital outputs by means of the network interfaces Serial CAN etc This parameter cannot be changed via HMI Each bit of this parameter corresponds to the desired value for one digital output In order to have the correspondent digital output controlled according to this content it is necessary that its function be programmed for PO695 Content at parameters P0275 to P0279 Function Reserved DOS setting DO4 setting DOS setting DO2 setting DO1 setting Table 3 5 P0695 parameter bit functions Bits es 2 0 DO1 output open 1 output closed DO2 output open 1 DO2 output closed DOS output open 1 output closed DO4 output open 1 DO4 output closed 005 output open
7. In those cases the master must detect the occurrence of the error by means of the timeout while waiting for the slave response In the event of a successful reception during the treatment of the telegram the slave may detect problems and send an error message indicating the kind of problem found Invalid function Error code 1 The requested function has not been implemented for the equipment Invalid datum address Error code 2 the datum address does not exist Invalid datum value Error code 3 It occurs in the following situations The value is out of the permitted range An attempt to write in a datum that cannot be changed reading only register bit NOTE 7 It is important that it be possible to identify at the master what type of error occurred in order to be able to diagnose problems during the communication In the event of any of those errors the slave must send a message to the master indicating the type of error that occurred The error messages sent by the slave have the following structure Request Master Response Slave Slave Address Slave Address Function Function with the most significant bit in 1 Error code Example the master requests to the slave at the address 1 the writing in the register 2900 nonexistent register Request Master Register low Value high Value low En NS Ce CFW700 23 mej Faults and Alarms Related to the Modbus RTU Communi
8. 10V to 10V negative values for this parameter must be used to command the output with negative voltage values i e 32768 to 32767 represent a variation from 10V to 10V at the analog output 2 Refer to the CFW700 manual for the product actual output resolution CFW700 15 Weg Modbus RTU Protocol 4 MODBUS RTU PROTOCOL The Modbus RTU protocol was initially developed in 1979 Nowadays it is a widely spread open protocol used by several manufactures in many equipments The CFW700 frequency inverter Modbus RTU communication was developed based on the following documents MODBUS Protocol Reference Guide Rev J MODICON June 1996 MODBUS Application Protocol Specification MODBUS ORG December 28th 2006 MODBUS over Serial Line MODBUS ORG December 20th 2006 In those documents is defined the format of the messages used by the elements that are constituent parts of the Modbus network the services or functions that can be made available and also how those elements exchange data in the network 41 TRANSMISSION MODES Two transmission modes are defined in the protocol specification ASCII and RTU The modes define the way the message bytes are transmitted It is not possible to use the two transmission modes in the same network The CFW700 frequency inverter uses only the RTU mode for the telegram transmission The bytes are transmitted in hexadecimal format and its configuration depends the programming done by m
9. 58 3A 3 90 5A 7 122 2 27 LB ESC Escape 59 3B 91 5B 123 7B 28 LC FS File Separator 60 92 5C 3 124 7 29 LD GS Group Separator 61 3D 93 5D 125 7D 30 LE RS Record Separator 62 3E 94 126 7 31 05 Unit Separator 63 3F 2 95 5F 2 127 DEL CFW700 25 Len Appendices APPENDIX B CRC CALCULATION USING TABLES Next a function using programming language is presented which implements the CRC calculation for the Modbus RTU protocol The calculation uses two tables to supply pre calculated values of the necessary displacement for the calculation The algorithm was obtained from and is explained in the documents referred to in the item 4 Table of CRC values for high order byte static unsigned char auchCRCHi 0x00 0 1 0x81 0x40 0x01 0 0 0x80 0x41 0x01 0 0 0x80 0x41 0x00 0x01 0 0 0x80 0x41 0x00 OxCl 0x81 0x40 0 00 OxCl 0 81 0x40 0 01 0x01 0 0 0x80 0x41 0x00 OxCl 0x81 0x40 0x00 OxCl 0x81 0x40 0x01 0x00 0 1 0x81 0x40 0 01 0 0 0x80 0x41 0x01 0 0 0x80 0x41 0x00 0x01 0 0 0x80 0x41 0x00 OxCl 0x81 0x40 0x00 OxCl 0x81 0x40 0x01 0x00 0 1 0x81 0x40 0 01 0 0 0x80 0x41 0x01 0 0 0x80 0x41 0x00 0x00 0 1 Ox81 0x40 0 01 0 0 0x80 0x41 0x01 0 0 0x80 0x41 0x00 0 01 0 0 0x8
10. CFW700 7 NETWORK CONNECTIONS Enable the termination resistors only at two points at the extremes of the main bus even if there are derivations from the bus CFW700 8 Programming 3 PROGRAMMING Next the CFW700 frequency inverter parameters related to the Modbus RTU communication will be presented 3 1 SYMBOLS FOR THE PROPERTIES DESCRIPTION RO Reading only parameter CFG Parameter that can be changed only with a stopped motor P0105 151 2 RAMP SELECTION P0220 LOCAL REMOTE SELECTION SOURCE P0221 SPEED REFERENCE SELECTION LOCAL SITUATION P0222 SPEED REFERENCE SELECTION REMOTE SITUATION P0223 FORWARD REVERSE SELECTION LOCAL SITUATION P0224 RUN STOP SELECTION LOCAL SITUATION P0225 JOG SELECTION LOCAL SITUATION P0226 FORWARD REVERSE SELECTION REMOTE SITUATION P0227 RUN STOP SELECTION REMOTE SITUATION P0228 JOG SELECTION REMOTE SITUATION These parameters are used in the configuration of the command source for the CFW700 frequency inverter local and remote situations In order that the device be controlled through the Modbus RTU interface the options serial available in these parameters must be selected The detailed description of these parameters is found in the CFW700 Programming Manual P0308 SERIAL ADDRESS Range 1 to 247 Default 1 Properties Access groups via HMI NET Description It allows programming the address used for the inv
11. NET Description It allows programming a time limit for the detection of serial interface communication error If the inverter remains without receiving valid telegrams longer than the time programmed in this parameter it will be considered that a communication error has occurred the alarm A128 will be showed on the HMI and the option programmed in P0313 will be executed After being powered up the inverter starts counting this time from the first received valid telegram The value 0 0 disables this function P0316 SERIAL INTERFACE STATUS Range O Inactive Default 1 Active 2 Watchdog error Properties RO Access groups via HMI NET Description It allows identifying whether the RS485 serial interface board is properly installed and whether the serial communication presents errors Table 3 2 P0316 options O Inactive Inactive serial interface It occurs when the device does not have the RS485 board installed Not used for CFW700 1 Active Installed and acknowledged RS485 interface board 2 Watchdog error The serial interface is active but a serial communication error has been detected A128 alarm F228 fault P0680 STATUS WORD Range 0000h to FFFFh Default Properties RO Access groups via HMI NET Description It allows the device status monitoring Each bit represents a specific status Function Fault condition Reserved Undervoltage LOC REM Motor Running In config
12. Range 0000h a FFFFh Default 0000h Properties Access groups via HMI NET Description It is the device Modbus RTU interface control word This parameter can only be changed via serial interface For the other sources etc it behaves like a read only parameter In order to have those commands executed it is necessary that the inverter be programmed to be controlled via serial This programming is achieved by means of parameters P0105 and P0220 to 228 Each bit of this word represents an inverter command that can be executed Function Bits 15808 7 6 8 8 5 6 gt Run Stop 2 Reserved Second ramp LOC REM gt General enable JOG Speed direction Table 3 4 P0682 parameter bit functions Bit O stops the motor with deceleration ramp Run Stop The motor runs according to the acceleration ramp until reaching the speed reference value 0 O It disables the drive interrupting the supply for the motor General enable 1 It enables the drive allowing the motor operation O To run the motor in a direction opposed to the speed reference Speed direction 1 To run the motor in the direction indicated by the speed reference JOG 1 It enables the JOG function LOC REM 1 The drive goes to the Remote mode Bit 5 O The drive uses the first ramp values programmed in P0100 and P0101 as the motor acceleration Second ramp and deceleration ramp times 1 The drive is con
13. The format and contents of this field depend on the used function and the transmitted value This field is described together with the function description refer to item 5 4 2 4 CRC The last part of the telegram is the field for checking the transmission errors The used method is the CRC 16 Cycling Redundancy Check This field is formed by two bytes where first the least significant byte is CFW700 16 Weg Modbus RTU Protocol transmitted CRC and then the most significant CRC The CRC calculation form is described in the protocol specification however information for its implementation is also supplied in the Appendix B 4 2 5 Time Between Messages In the RTU mode there is no specific character that indicates the beginning or the end of a telegram The indication of when a new message begins or when it ends is done by the absence of data transmission in the network for a minimum period of 3 5 times the transmission time of a data byte 11 bits Thus in case a telegram has initiated after the elapsing of this minimum time the network elements will assume that the first received character represents the beginning of a new telegram And in the same manner the network elements will assume that the telegram has reached its end when after receiving the telegram elements this time has elapsed again If during the transmission of a telegram the time between the bytes is longer than this minimum time the telegram will be co
14. OxE2 OxE3 0x23 1 0 0 0x60 0x61 OxAl 0x63 OxA2 0x62 0x66 OxA6 0 7 0x67 OxA5 Ox6C OxAD 0x6D OxAF 0 6 Ox6E OxAE 0 6 Ox6B 0x69 0x78 0 8 OxB9 0x79 0 0 7 0 7 0 OxBE 0 7 0 7 0x7D OxB4 0x74 0 75 0 5 0 77 0 7 OxB6 Ox76 0x72 0 2 OxB3 0x73 OxB1 0x50 0x90 0x91 0 51 0x93 0 53 0x52 0x92 0x96 0x56 0 57 0x97 0x55 0 9 0 5 0x5D 0 9 0 5 Ox9F 0 9 0x5E 0x5A 0 9 0 9 Ox5B 0x99 0x88 0x48 0x49 0x89 0x4B Ox8B 0 8 0x4A 0x4E 0 8 Ox8F 0x4F 0x8D 0x44 0x84 0x85 0x45 0x87 0x47 0x46 0x86 0x82 0x42 0x43 0x83 0x41 0x81 The function returns the CRC as a unsigned short type unsigned short CRC16 puchMsg usDataLen unsigned char puchMsg message to calculate CRC upon unsigned short usDataLen quantity of bytes in message unsigned char uchCRCHi OxFF high byte of CRC initialized unsigned char uchCRCLo low byte of CRC initialized 24 unsigned will index into CRC lookup table while usDataLen pass through message buffer uIndex uchCRCLo puchMsgg calculate the CRC uchCRCLo uchCRCHi auchCRCHi uIndex uchCRCHi auchCRCLo uIndex return uchCRCHi lt lt 8 uchCRCLo 7 1 0 0 0 0 0 1 OxCo 0 1 1 0 0 0 0
15. 0 0x41 0x00 OxCl 0x81 0x40 0x00 0 1 0x81 0x40 0x01 0x01 0 0 0x80 0x41 0x00 OxCl 0x81 0 40 0 00 OxCl 0 81 0x40 0 01 0 00 0 1 0 81 0x40 0 01 0 0 0 80 0 41 0x01 0 0 0 80 0 41 0 00 0 00 0 1 0x81 0x40 0x01 0 0 0 80 0 41 0 01 0 0 0 80 0x41 0 00 0x01 0 0 0x80 0x41 0x00 0 1 0x81 0x40 0x00 OxCl 0x81 0 40 0x01 0x00 0 1 0x81 0x40 0 01 0 0 0x80 0x41 0x01 0 0 0x80 0x41 0 00 0 01 0 0 0x80 0x41 0x00 OxCl 0x81 0x40 0x00 OxCl 0x81 0x40 0x01 0x01 0 0 0x80 0x41 0x00 OxCl 0x81 0x40 0 00 OxCl 0 81 0x40 0 01 0x00 0 1 0x81 0x40 0x01 0 0 0x80 0x41 0x01 0 0 0x80 0x41 0x00 0 1 Table of CRC values for low order byte static char auchCRCLo 0x00 0 0 OxCl 0x01 OxC3 0x03 0 02 0 2 0 6 0x06 Ox07 0 7 0x05 0 0 0 Ox0D OxCD 0 0 OxCF OxCE 0 0 0x0A 0 OxCB Ox0B OxC9 OxD8 0x18 0x19 OxD9 0x1B OxDB OxDA 0 1 0 1 OxDE OxDF 0 1 OxDD 0x14 0 4 OxD5 0 15 OxD7 0 17 0x16 OxD6 OxD2 0x12 0 13 0xD3 0 11 OxFO 0x30 0 31 0xF1 0x33 OxF3 OxF2 0x32 0x36 OxF6 OxF7 0x37 OxF5 0x3C OxFC OxFD 0x3D OxFF Ox3F Ox3E OxFE OxFA 0x3A 0x3B OxFB 0x39 0x28 0 8 OxE9 0x29 OxEB 0x2B 0 2 0 0 2 0 2 OxEF 0x2D OxE4 0x24 0 25 0 5 0x27 0 7 OxE6 0x26 0x22
16. 1 1 0xC0 0 1 0 0 0 0 0 81 0x09 0x1D OxD1 0x35 0 9 OxED Ox21 0x65 0 9 OxBD 0 71 0 95 0 59 0x4D 0x80 0x81 0x80 0x80 0x81 0x80 0x81 0x81 0x80 0x80 0x81 0x81 0x80 0x81 0x80 0x80 0x40 0 4 0 08 0 1 0 0 0 34 0 8 0 0 20 0 64 0 8 OxBC 0x70 0x94 0x58 4 0 40 0 40 0 41 0 41 0 40 0 41 0 40 0 40 0 41 0 41 0x40 0x40 0x41 0x40 0x41 0x41 0x04 0xc8 OxDC 0x10 0 4 0 38 Ox2C 0 0 0 4 0 68 Ox7C OxBO 0x54 0x98 0 8 CFW700 26 WEG Equipamentos El tricos S A Jaragu do Sul SC Brasil Fone 55 47 3276 4000 Fax 55 47 3276 4020 S o Paulo SP Brasil Fone 55 11 5053 2300 Fax 55 11 5052 4212 automacao weg net www weg net
17. 1 DO5 output closed CFW700 14 Programming P0696 VALUE 1 FOR ANALOG OUTPUTS P0697 VALUE 2 FOR ANALOG OUTPUTS Range 32768 to 32767 Default O Properties RW Access groups via HMI NET Description They allow the control of the analog outputs by means of network interfaces Serial CAN etc These parameters cannot be changed via The value written in these parameters is used as the analog output value providing that the function for the desired analog output be programmed for P0696 P0697 value at the parameters P0251 P0254 The value must be written in a 15 bit scale 7FFFh 32767 to represent 100 of the output desired value P0696 0000h 0 decimal analog output value 0 P0696 7FFFh 32767 decimal analog output value 100 The showed example was for P0696 but the same scale is also used for the parameters PO697 For instance to control the analog output 1 via serial the following programming must be done Choose a parameter from P0696 0697 to be the value used by the analog output 1 For this example we are going to select 696 Program the option P0696 value as the function for the analog output 1 in P0254 Using the network interface write in P0696 the desired value for the analog output 1 between 0 and 100 according to the parameter scale NOTE 7 If the analog output is programmed for working from
18. 44444444588644445454444 14 88 4 3 16 4 2 2 Function COG 16 4 2 3 Data E E E E E E E E E 16 4 2 4 CRO E A O E E E O E SO 16 4 2 5 Time Between 17 5 OPERATION IN THE MODBUS NETWORK SLAVE MODE 18 5 1 AVAILABLE FUNCTIONS AND RESPONSE 18 CFW700 Contents 5 2 18 6 DETAILED DESCRIPTION OF THE 20 6 1 FUNCTION 03 READ HOLDING 20 6 2 FUNCTION 06 WRITE SINGLE REGISTER 20 6 3 FUNCTION 16 WRITE MULTIPLE 21 6 4 FUNCTION 43 READ DEVICE 22 6 5 COMMUNICATION
19. Motors Automation Energy Transmission amp Distribution Coatings Modbus RTU CFW700 User s Manual E ERG et E Modbus RTU User s Manual series 700 Language English Document Number 10001123706 01 Publication Date 05 2011 Contents CONTENTS CONTENTS 3 ABOUT THIS 5 ABBREVIATIONS AND 5 NUMERICAL REPRESENTATION 1 1 1 1 1 61111 nnna 5 1 INTRODUCTION SERIAL 6 2 NETWORK 7 21 R9485 45 64 7 2 1 1 RS485 Interface Characteristics 7 21 2 Connector PINOUT 52222252
20. cation 7 FAULTS AND ALARMS RELATED TO THE MODBUS RTU COMMUNICATION A128 F228 SERIAL COMMUNICATION TIMEOUT Description It is the only alarm fault related to the serial communication It indicates that the device has stopped receiving valid serial telegrams for a period longer than the programmed in P0314 Working The parameter P0314 allows the programming of a period during which the slave must receive at least one valid telegram via the RS 232 or 5 485 serial interface with address and error checking field correct otherwise it will be considered that there was any problem in the serial communication The time counting initiates after the reception of the first valid telegram After the timeout for serial communication is identified the alarm 128 or the fault F228 depending on the P0313 programming will be signalized through the HMI In case of alarms if the communication is reestablished and new valid telegrams are received the alarm indication will be removed from the HMI Possible causes correction Verify factors that could cause failures in the communication cables installation and grounding Make sure that the master sends telegrams to the slave in intervals shorter than the programmed in P0314 Disable this function in P0314 CFW700 24 Appendices APPENDICES APPENDIX A ASCII TABLE Table 1 1 ASCII Characters
21. ddress Function Address of the initial register high byte Address of the initial register low byte Number of registers high byte Number of registers low byte CRC CRC etc RO Example reading of the motor speed P0002 and the motor current 003 of slave at address 1 assuming that POOO2 1000 rpm and 3 5 Address 1 Oth 1 byte Number of the first parameter 2 0002h 2 bytes Value of the fist parameter 1000 O3E8h 2 bytes Value of the second parameter 35 0023h 2 bytes RA 6 2 FUNCTION 06 WRITE SINGLE REGISTER This function is used to write a value for a single register It has the following structure each field represents a byte CFW700 20 Detailed Description of the Functions Example writing of 900 rpm as the speed reference P0683 assuming a synchronous speed of 1800 rpm for the slave at address Address 08h 1 byte Parameter number 683 2 2 bytes Value for parameter 1000h 2 bytes Note that for this function the slave response is an identical copy of the request made by the master 6 3 FUNCTION 16 WRITE MULTIPLE REGISTERS This function allows writing values for a group of registers which must be in a numerical sequence It can also be used to write in a single register each field represents a byte Datum 1 low Datum 2 high Datum 2 low etc CRC Example writing o
22. eans of P0311 4 2 MESSAGE STRUCTURE FOR RTU MODE The Modbus RTU structure uses a master slave system for message exchange It allows up to 247 slaves but only one master Every communication begins with the master making a request to a slave which answers to the master what has been asked In both telegrams request and answer the used structure is the same Address Function Code Data and CRC Only the data field can have a variable size depending on what is being requested Master request telegram Address Function Request Data CRC 1 byte 1 byte n bytes 2 bytes Slave response telegram Address Function Response Data CRC 1 byte 1 byte n bytes 2 bytes 4 2 1 Address The master initiates the communication sending a byte with the address of the slave to which the message is destined When sending the answer the slave also initiates the telegram with its own address The master can also send a message to the address O zero which means that the message is destined to all the slaves in the network broadcast In that case no slave will answer to the master 4 2 2 Function Code This field also contains a single byte where the master specifies the kind of service or function requested to the slave reading writing etc According to the protocol each function is used to access a specific type of data For the available list of supported functions refer to item 5 4 2 3 Data Field It is a variable size field
23. ent More devices be connected by using repeaters A maximum bus length of 1000 meters 2 1 2 Connector pinout The RS485 interface is available at the 1 connector with the following connections Table 2 1 5485 connector pinout B Line RxD TxD positive OV isolated from the RS485 circuit Name Function 9 21 3 Terminating resistor It is necessary to enable a terminating resistor at both ends of the main bus for each segment of the RS485 network There are switches the CFW700 frequency inverter that can be activated by placing both switches S2 to ON to enable the terminating resistor Figure 2 1 Terminating Resistor and RS485 connector 2 1 4 Connection with the RS485 Network The following points must be observed for the connection of the device using the RS485 interface t is recommended the use of a shielded cable with a twisted pair of wires Itis also recommended that the cable has one more wire for the connection of the reference signal GND In case the cable does not have the additional wire then the GND signal must be left disconnected cable must be laid separately and far away if possible from the power cables All the network devices must be properly grounded preferably at the same ground connection The cable shield must also be grounded 1 The limit number of devices that can be connected to the network depends also on the used protocol
24. erter serial communication It is necessary that each device in the network has an address different from all the others P0310 SERIAL BAUD RATE Range O 9600 bits s Default 1 1 19200 bits s 2 38400 bits s 3 57600 bits s Properties Access groups via HMI NET Description It allows programming the baud rate for the serial communication interface in bits per second This baud rate must be the same for all the devices connected to the network CFW700 9 mej Programming P0311 SERIAL INTERFACE BYTE CONFIGURATION Range O 8 data bits no parity 1 stop bit Default O 1 8 data bits even parity 1 stop bit 2 8 data bits odd parity 1 stop bit 3 8 data bits no parity 2 stop bits 4 8 data bits even parity 2 stop bits 5 8 data bits odd parity 2 stop bits Properties CFG Access groups via HMI NET Description It allows programming the number of data bits parity and stop bits of the serial interface bytes This configuration must be identical for all the devices connected to the network P0313 COMMUNICATION ERROR ACTION Range O Inactive Default O 1 Disable via Run Stop 2 Disable via General Enable 3 Change to Local 4 Change to Local keeping commands and reference 5 Causes a Fault Properties CFG Access groups via HMI NET Description It allows the selection of the action to be executed by the device if it is controlled via network and a communication error
25. f the acceleration time P0100 equal to 1 0s and the deceleration time P0101 equal to 2 0s of a slave at address 15 Address 15 OFh 1 byte First parameter number 100 0064h 2 bytes Value for the fist parameter 10 OOOAh 2 bytes Value for the second parameter 20 0014h 2 bytes Field low Jon po Pott 300 per CFW700 21 Detailed Description of the Functions 6 4 FUNCTION 43 READ DEVICE IDENTIFICATION It is an auxiliary function that allows the reading of the product manufacturer model and firmware version It has the following structure Code of the first object 00 04 Size of the 00 2 Value of the first object n bytes Code of the second object Size ofthesecondobject 0 24 Value of the second object n bytes This function allows the reading of three information categories Basic Regular and Extended and each category is formed by a group of objects Each object is formed by a sequence of ASCII characters For the CFW 700 frequency inverter only basic information formed by three objects is available Objeto 00h VendorName represents the product manufacturer Objeto O1h ProductCode formed by the product code CFW700 plus the inverter rated voltage current CFW700 220 230 10 Objeto 02h MajorMinorRevision it indicates the product fir
26. figured to use the second ramp values programmed in P0102 and P0103 as the motor acceleration and deceleration ramp times Bit 6 O It does not execute the fast stop command Fast stop 1 It executes the fast stop command Note This function is not allowed with control types P0202 V f or VVW Bit 7 O No function Fault reset 1 If in a fault condition then it executes the drive reset Bits 8 to 15 P0683 SERIAL SPEED REFERENCE Range 32768 a 32767 Default O Properties Access groups via HMI NET Description It allows programming the motor speed reference via the Modbus RTU interface This parameter can only be changed via serial interface For the other sources HMI etc it behaves like a read only parameter In order that the reference written in this parameter be used it is necessary that the drive be programmed to use the speed reference via serial This programming is achieved by means of parameters P0221 and P0222 This word uses a 13 bit resolution with signal to represent the motor synchronous speed CFW700 13 Programming P0683 0000h 0 decimal speed reference 0 P0683 2000h 8192 decimal speed reference synchronous speed Intermediate or higher reference values can be programmed by using this scale E g for a 4 pole 1800 rpm synchronous speed motor to obtain a speed reference of 900 rpm one must calculate 1800 rpm gt 8192 900 rpm gt 13 bit reference
27. is detected Table 3 1 13 options Options Description 2 No action is taken and the inverter remains in the existing status motor stops according to the programmed deceleration ramp motor coasts to stop 3 Change to Local The inverter commands change to Local 4 Change to Local keeping The inverter commands change to Local but the status of the commands and reference enabling and speed reference commands received via network are kept providing that the inverter has been programmed to use in Local mode the commands via and speed reference via either HMI 5 Causes a Fault Instead of an alarm the communication error causes an inverter fault so that an inverter fault reset becomes necessary in order to restore normal operation The following events are considered communication errors Serial communication RS485 128 alarm F228 fault Serial communication timeout The actions described in this parameter are executed by means of the automatic writing of the selected actions in the respective bits of the interface control words Therefore in order that the commands written in this parameter be effective it is necessary that the device be programmed to be controlled via the used network interface This programming is achieved by means of parameters P0220 to P0228 CFW700 10 Programming P0314 SERIAL WATCHDOG Range 0 0 to 999 0s Default 0 0 Properties Access groups via HMI
28. kers word or float can also be accessed using the Modbus RTU interface Those markers are used mainly by the SoftPLC function available for the CFW700 Refer to the SoftPLC Manual for the description of those markers as well as for the addresses via Modbus CFW700 19 Detailed Description of the Functions 6 DETAILED DESCRIPTION OF THE FUNCTIONS A detailed description of the functions available in the CFW700 frequency inverter for the Modbus RTU is provided in this section In order to elaborate the telegrams it is important to observe the following The values are always transmitted in hexadecimal The address of a datum the number of data and the value of registers are always represented in 16 bits Therefore it is necessary to transmit those fields using two bytes superior high and inferior low telegrams for request as well as for response cannot exceed 64 bytes transmitted values are always integer regardless of having a representation with decimal point Thus the value 9 5 would be transmitted via serial as being 95 Refer to the CFW700 parameter list to obtain the resolution used for each parameter 6 1 FUNCTION 03 READ HOLDING REGISTER It reads the content of a group of registers that must be necessarily in a numerical sequence This function has the following structure for the request and response telegrams each field represents a byte Request Master Slave A
29. llustrates the parameters addressing which can be accessed as holding type register Functions used to access SoftPLC data CFW700 18 Operation in the Modbus RTU Network Slave Mode Table 5 1 Modbus RTU Memory Map Parameter n mber Modbus data address Hexadecimal It is necessary to know the inverter list of parameters to be able to operate the equipment Thus it is possible to identify what data are needed for the status monitoring and the control of the functions The main parameters are Monitoring reading P0680 holding register 680 Status word P0681 holding register 681 Motor speed Command writing P0682 holding register 682 Command Word P0683 holding register 683 Speed Reference Refer to the Programming Manual for a complete parameter list of the equipment NOTE All the parameters are treated as holding type registers Depending the master that is used those registers are referenced starting from the base address 40000 or 4x In this case the address that must be programmed in the master for a parameter is the address showed in the table above added to the base address Refer to the master documentation to find out how to access holding type registers It should be noted that read only parameters can only be read from the equipment while other parameters can be read and written through the network Besides the parameters other types of data as bit mar
30. made available Read Coils Description reading of bit blocks of the coil type Function code 01 Read Discrete Inputs Description reading of bit blocks of the discrete input type Function code 02 Read Holding Registers Description reading of register blocks of the holding register type Function code 03 Read Input Registers Description reading of register blocks of the input register type Function code 04 Write Single Coil Description writing in a single bit of the coil type Function code 05 Write Single Register Description writing in a single register of the holding type Function code 06 Write Multiple Coils Description writing in bit blocks of the coil type Function code 15 Write Multiple Registers Description writing in register blocks of the holding register type Function code 16 Read Device Identification Description identification of the device model Function code 43 The response time from the end of transmission of the master until the response of the slave ranges from 2 to 10 ms for any of the functions above 5 2 MEMORY The CFW700 Modbus communication is based on the reading writing of the equipment parameters All the drive parameters list is made available as holding type 16 bit registers The data addressing is done with the offset equal to zero which means that the parameter number corresponds to the register number The following table i
31. mware version in the format The reading code indicates what information categories are read and if the objects are accessed in sequence or individually The CFW700 supports the codes 01 basic information in sequence and 04 individual access to the objects The other fields are specified by the protocol and for the CFW700 they have fixed values Example reading of basic information in sequence starting from the object 02h from a CFW700 at address 1 127 Numberofobjots 0 1 Oeo Opte 1 7 0 CRC In this example the value of the objects was not represented in hexadecimal but using the corresponding ASCII characters instead E g for the object 02h the value 1 00 was transmitted as being five ASCII characters which in hexadecimal have the values 56h V 31h 1 2Eh 30h 0 and 30h 09 6 5 COMMUNICATION ERRORS Communication errors may occur in the transmission of telegrams as well as in the contents of the transmitted telegrams Depending on the type of error the slave may or not send a response to the master CFW700 22 Detailed Description of the Functions When the master sends a message for an inverter configured in a specific network address the product will not respond to the master if the following occurs Parity bit error CRC error Timeout between the transmitted bytes 3 5 times the transmission time of a byte
32. nsidered invalid because the frequency inverter will discard the bytes already received and will mount a new telegram with the bytes that were being transmitted For communication rates higher than 19200 bits s the used times are the same as for that rate The next table shows us the times for different communication transmission rates Thetweenbytes 5 a Transmission Signal Time T11 bits r Telegram Table 4 1 Communication rates and the time periods involved in the telegram transmission Thi bits Time for transmitting one byte of the telegram Trewmeenbyes Time between bytes Tax Minimum interval to indicated beginning and end of a telegram 3 5 x T1 1 bits CFW700 17 Operation in the Modbus RTU Network Slave Mode 5 OPERATION IN THE MODBUS RTU NETWORK SLAVE MODE CFW700 frequency inverter has the following characteristics when operated Modbus RTU network Network connection via RS485 serial interface Address communication rate and byte format defined by means of parameters t allows the device programming and control via the access to parameters 5 1 AVAILABLE FUNCTIONS AND RESPONSE TIMES In the Modbus RTU specification are defined the functions used to access different types of data In the CFW700 the parameters have been defined as being holding type registers In order to access those data the following services or functions have been
33. on 1 INTRODUCTION TO SERIAL COMMUNICATION In a serial interface the data bits are sent sequentially through a communication channel or bus Several technologies use the serial communication for data transfer including the 5232 and 5485 interfaces The directions that specify the RS232 and RS485 standards however do neither specify the character format nor its sequence for the data transmission and reception Therefore besides the interface it is also necessary to identify the protocol used for the communication Among the several existent protocols one used a lot in the industry is the Modbus RTU protocol In the sequence the characteristics of the RS485 serial interface available for the product will be presented as well as the Modbus RTU protocol for the use of this interface 700 6 NETWORK CONNECTIONS 2 NETWORK CONNECTIONS The CFW700 frequency inverter has a standard RS485 interface Information about the connection installation of the inverter to the network is presented bellow 21 RS485 211 RS485 Interface Characteristics interface follows the EIA 485 standard t operates as a slave in the Modbus RTU network t allows communication baud rates from 9600 up to 57600 Kbit s The interface is electrically isolated and with differential signal which grants more robustness against electromagnetic interference t allows the connection of up to 32 devices to the same segm
34. ot active Active General Enable 1 General Enable is active and the inverter is ready to run the motor Bit 10 0 The motor is running in the reverse direction Speed direction 1 The motor is running in the forward direction JOG 1 Active JOG function LOC REM 1 Drive in Remote mode Bit 13 0 No Undervoltage Undervoltage 1 With Undervoltage Bit 14 Reserved Reserved Bit 15 0 The drive is not in a fault condition Fault condition 1 The drive has detected a fault Note The fault number be read by means of the parameter P0049 Present Fault P0681 MOTOR SPEED IN 13 BITS Range 32768 to 32767 Default Properties RO Access groups via HMI NET Description It allows monitoring the motor speed This word uses 13 bit resolution with signal to represent the motor synchronous speed P0681 0000h 0 decimal motor speed O P0681 2000h 8192 decimal motor speed synchronous speed Intermediate or higher speed values in rpm can be obtained by using this scale E g for a 4 pole 1800 rpm synchronous speed motor if the value read is 2048 0800h then to obtain the speed in rpm one must calculate 8192 gt 1800 rpm 2048 gt Speed in rpm Speed in rpm 1800 x 2048 8192 Speed in rom 450 rpm Negative values in this parameter indicate that the motor is running in the reverse direction CFW700 12 Programming P0682 SERIAL CONTROL WORD
35. uration Second ramp o Reserved Speed direction Active General Alarm condition CFW700 11 Weg Programming Table 3 3 PO680 parameter bit functions Active fast stop 1 The drive is executing the fast stop command Bit 5 0 The drive is configured to use the first ramp values programmed in P0100 and P0101 as the motor Second ramp acceleration and deceleration ramp times 1 The drive is configured to use the second ramp values programmed in P0102 and P0103 as the motor acceleration and deceleration ramp times Bit 6 0 The drive is operating normally In configuration mode 1 The drive is in the configuration mode It indicates a special condition during which the inverter cannot be enabled Executing the self tuning routine Executing the oriented start up routine Executing the HMI copy function Executing the flash memory card self guided routine There is a parameter setting incompatibility There is no power at the drive power section Note It is possible to obtain the exact description of the special operation mode at the parameter P0692 Bit 7 O The drive is not in alarm condition Alarm condition 1 The drive is in alarm condition Note The alarm number can be read by means of the parameter P0048 Present Alarm Bit 8 0 The motor is stopped Motor Running 1 The drive is running the motor at the set point speed or executing either the acceleration or the deceleration ramp Bit 9 O General Enable is n
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