SCA06 - Modbus RTU Manual
Contents
1. 20 7 FAULTS AND ALARMS RELATED THE MODBUS COMMUNICATION 22 00128 00028 SERIAL COMMUNICATION TIMEOUT 22 1 APPENDICES anivniisasanstssedeasncsedsastanatessnennceseianasanntsnnsanndansdsnanapnsinsbanatacshanasanniineianntaesiens 23 APPENDIX A ASCIITABLE wicccssiistcssistsscesctecscsssesscenssscsesesstvsncrnsiedensssasvsnnrsecuescsuanesuacdaddesecssivencvadsensseaie 23 APPENDIX CRC CALCULATION USING 24 8 06 4 About this Manual ABOUT THIS MANUAL This manual supplies the necessary information for the operation of the SCAO6 servo drive using the Modbus protocol This manual must be used together with the SCAO6 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 Binary numbers are represented with the letter b after the number DOCUMENTS The Modbus RTU protocol was developed based on the following specifications and docu2. 22 9 2 3 5 Connection 5485 nana aaa 9 3 25 10 3 1 SYMBOLS FOR THE PROPERTIES 10 650 SERVO DRIVE ADDRESS IN THE SERIAL COMMUNICATION 1 85232 10 P00656 SERVO DRIVE ADDRESS IN THE SERIAL COMMUNICATION 2 85485 10 P00652 RATE SERIAL 1 5232 10 00658 RATE SERIAL 2 5485 10 00653 SERIAL CONFIGURATION 1 85232 11 00659 SERIAL CONFIGURATION 2 RS485 11 00654 SELECT SERIAL PROTOCOL 1 5232 11 00660 SELECT SERIAL PROTOCOL 2 485 11 P0662 ACTION FOR COMMUNICA
3. 14 425 Time Between 55 14 5 OPERATION IN THE MODBUS RTU NETWORK SLAVE MODE 16 5 1 AVAILABLE FUNCTIONS AND RESPONSE 16 52 MEMORY 16 SCAO6 3 Len Contents 6 DETAILED DESCRIPTION OF THE FUNCTIONS 18 6 1 FUNCTION 03 READ HOLDING 18 6 2 FUNCTION 06 WRITE SINGLE REGISTER 1 18 6 3 FUNCTION 16 WRITE MULTIPLE 5 5 2242 19 6 4 FUNCTION 43 READ DEVICE 2 20 6 5 COMMUNICATION
4. 1 Do not connect the reserved pins 2 The limit of devices that can be connected to the network also depends on the used protocol 6 8 NETWORK CONNECTIONS Table 2 4 Connector pin assignment for RS485 123 Pin 2 SDS 6 Reserved 20028 9 Bates 2 3 4 Termination resistor For each segment of the RS485 network it is necessary to enable a termination resistor at the ends of the main bus The accessory ECO1 has two DIP Switches that can be activated by putting both SA121 switches in the ON position to enable the termination resistor Figure 2 1 Termination resistor 2 3 5 Connection to the RS485 Network For the connection of the servo drive SCAO6 using the RS485 interface the following points must be observed It s recommended to use a cable with shielded twisted pair also recommended that the cable have an additional wire for connecting the reference signal GND If the cable doesn t have the additional wire you should leave the GND signal disconnected passage of the cable must be done separately and if possible distant from the power supply cables All network devices must be properly grounded preferably to the same connection with the ground The cable shield must also be grounded Enable the termination resistors only in two points at the ends of the main bus even if there are derivations from the bus
5. 0x94 0x58 0x4C 0x40 0x40 0x41 0x41 0x40 0x41 0x40 0x40 0x41 0x41 0x40 0x40 0x41 0x40 0x41 0x41 0x04 OxC8 OxDC 0x10 0 4 0 38 Ox2C 0 0 OxA4 0x68 Ox7C OxBO 0x54 0x98 0x8C 8 06 24 WEG Equipamentos El tricos S A Jaragu do Sul SC Brazil Phone 55 47 3276 4000 Fax 55 47 3276 4020 S o Paulo SP Brazil Phone 55 11 5053 2300 Fax 55 11 5052 4212 automacao weg net www weg net
6. 1 1 Parameter is saved in non volatile memory Properties RW Description It allows selecting if the writing of parameters via serial must save the content of the parameters in the non volatile memory EEPROM or not When using the Modbus protocol it is only this parameter that determines if the parameters written via serial will be saved or not in the non volatile memory However when using the WEGTP protocol it must be observed that the information about saving or not the parameter in the EEPROM is contained in the telegram code byte In order to save them in non volatile memory via WEGTP it is necessary that these two pieces of information the telegram code byte and the parameter 4 be true NOTE 7 This type of memory features a limited number of records 100 000 times Depending the application this limit can be exceeded if some parameters are written cyclically via serial speed torque reference etc In these cases it may be desired that during the operation of the servo drive the writing via serial does not save the content of the parameters in non volatile memory so as not to exceed the number of writings on the servo drive NOTE 7 This parameter does not apply when writing is performed using the USB interface P00667 SAVE ON MARKERS Range O Reads and writes normally the content on the corresponding parameter Default O 1 Reads and writes content in volatile WORD markers from
7. 2 bytes Value for the second parameter 4 0004h 2 bytes Value for the third parameter 10 OOOAh 2 bytes Fela 8 06 19 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 ete 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 SCAO6 servo drive only basic information formed by three objects is available Objeto 00h VendorName represents the product manufacturer Objeto 01h ProductCode formed by the product code SCAO6 Objeto 02h MajorMinorRevision it indicates the product firmware version in the format The reading code indicates what information categories are read and if the objects are accessed in sequence or individually The SCAO6 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 SCAO6 they have fixed valu
8. 40 0 00 OxCl 0 81 0x40 0 01 0 00 0 1 0x81 0 40 0x01 0 0 0x80 0x41 0x01 0 0 0x80 0 41 0x00 0x01 0 0 0x80 0x41 0x00 OxCl 0x81 0x40 0x00 OxCl 0x81 0x40 0x01 0x01 0 0 0x80 0x41 0x00 OxCl 0x81 0x40 0x00 OxCl 0x81 0x40 0x01 0x00 0 1 0x81 0x40 0x01 0 0 0x80 0x41 0x01 0xC0 0x80 0x41 0x00 1 Table of CRC values for low order byte static char auchCRCLo 0x00 0 0 OxCl 0x01 OxC3 0x03 0x02 OxC2 0 6 0 06 0 07 OxC7 0 05 0 0 0 0 00 OxCD 0 0 OxCF OxCE 0 0 0x0A 0 OxCB Ox0B OxC9 OxD8 0 18 0x19 0xD9 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 0 0 0x30 0 31 0 1 0x33 OxF3 0 2 0x32 0x36 OxF6 OxF7 0 37 OxF5 0x3C OxFC OxFD 0x3D Ox3F Ox3E OxFE OxFA 0x3A 0 3 OxFB 0x39 0x28 0 8 OxE9 0x29 OxEB 0x2B 0 2 0 0 2 Ox2F 0x2D OxE4 0x24 0 25 0 5 0x27 0 7 OxE6 0x26 0x22 OxE2 OxE3 0x23 1 0 0 0x60 0x61 0 1 0x63 OxA3 OxA2 0x62 0x66 0 6 OxA7 0x67 OxA5 0x6C OxAC OxAD 0x6D OxAF 0 6 0 6 OxAE OxAA Ox6B 0x69 0x78 0 8 OxB9 0x79 0 0 7 0 7 OxBA OxBE 0 7 0 7 OxBF Ox7D OxB4 0x74 0 75 0 5 0 77 0 7 OxB6 Ox76 0x72 0 2 OxB
9. 544034 42418 2 dar 7 2 2 1 IACI GATIONS sore 7 2 2 2 Connection to RS232 7 2 2 3 Cables for Connection in 85232 7 2 2 4 Connector Pin 54 7 23 5485 E 8 2 3 1 IACI GATIONS cao dica 4 53544542 558 53434215 4335 185 4 1 5 inn 8 2 3 2 Characteristics of RS485 8 2 3 3 Connector Pin 518 4 545 4 458 55 44484584 44854 42444454444548254 4544 44468 48 8 2 3 4 Termination
10. 127 DEL SCAO6 23 Appendices APPENDIX B CRC CALCULATION USING TABLES Next a function using programming language C 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 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 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 01 0 0 0x80 0x41 0x00 OxCl 0x81 0 40 0 00 OxCl 0 81 0x40 0 01 0x00 0 1 0x81 0x40 0x01 0 0 0x80 0x41 0x01 0 0 0x80 0x41 0x00 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 0x00 OxCl 0x81 0x40 0x01 0x01 0 0 0x80 0x41 0 00 OxCl 0x81 0x40 0x00 OxCl 0x81 0x40 0 01 0x00 0 1 Ox81 0x40 0 01 0 0 0 80 0 41 0x01 0 0 0 80 0x41 0 00 0 00 0 1 Ox81 0 40 0 01 0 0 0 80 0 41 0 01 0 0 0 80 0 41 0 00 0 01 0 0 0x80 0x41 0 00 OxCl 0x81 0
11. P00653 SERIAL CONFIGURATION 1 RS232 P00659 SERIAL CONFIGURATION 2 RS485 Range O 8 data bits no parity 1 stop bit Default 3 1 8 data bits parity even 1 stop bit 2 8 data bits parity odd 1 stop bit 3 8 data bits no parity 2 stop bits 4 8 data bits parity even 2 stop bits 5 8 data bits parity odd 2 stop bits 6 7 data bits no parity 1 stop bit 7 7 data bits parity even 1 stop bit 8 data bits parity odd 1 stop bit 9 data bits no parity 2 stop bits 10 7 data bits parity even 2 stop bits 11 7 data bits parity odd 2 stop bits Properties RW AC Description It allows the configuration of the number of data bits parity and stop bits in the bytes of the serial interface This configuration must be the same for all the devices connected to the network P00654 SELECT SERIAL PROTOCOL 1 RS232 P00660 SELECT SERIAL PROTOCOL 2 RS485 Range 1 WEGTP Default 1 2 Modbus RTU Properties RW Description It allows selecting the desired protocol for the serial interface The detailed description of the protocol is presented in item 4 of this manual P0662 ACTION FOR COMMUNICATION ERROR Range O Cause Alarm Default O 1 Cause Fault 2 Cause alarm and execute STOP 3 Cause alarm and disable drive Properties Description This parameter allows selecting which action must be executed by the equipment in case it is controlled via network and a communication
12. and communication module ECO1 described below Information about the installation of this module can be obtained in the guide that comes with the accessory 2 1 EXPANSION AND COMMUNICATION RS232 AND RS485 ECO1 MODULE Item 11330271 Composed by the communication module ECO1 in the figure beside and one assembly guide insulated interface and with differential signal providing more resistance against electromagnetic interference The RS232 and RS485 signals are independent channels and they may be used simultaneously 22 RS232 2214 Indications LED LA121 indicates lights when there is data transmission by the RS232 communication 2 2 2 Connection to the RS232 Network inverter signals RX and TX must be respectively connected to the TX and RX signals of the master besides the connection of the reference signal GND interface RS232 is very susceptible to interferences For this reason the cable used for communication should be as short as possible always shorter than 10 meters and must be placed separately from power wiring that feeds the inverter and the motor 223 Cables for Connection in RS232 If desired items of the following cables are available for connection in RS232 between the servo drive and a network master like a PC Table 2 1 RS232 Cable Cable RS232 shielded cable with DB9 connectors 10050328 Length 3 meters RS232 shielded cab
13. the MW13000 Properties RW Description Property verified when parameter is written and read via serial It selects whether the content to be written read must be saved on parameter or in volatile WORD marker NOTE 7 this parameter POO667 1 when writing in parameter 105 30 serial the content of the parameter will be stored in the Word marker 13105 Initial MW Even number gt 13000 105 Therefore MW13105 30 5 06 12 eq Programming Note Once 1 it cannot be changed via serial Because when trying to write in parameter you will be writing in Word marker P13667 8 06 13 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 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 SCAO6 servo drive uses only the RTU mode for the telegram transmission The bytes are transmitted in hexadecimal format and its configuration depends the programming done by means of 4 2 MESSAGE STRUCTURE FOR RTU MODE The Modbus RTU structure uses a master slave system for message exchange It allows up
14. 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 The format and contents of this field depend on the used function and the transmitted value This field is described together with th
15. 3 0x73 OxB1 0x50 0x90 0 91 0 51 0x93 0x53 0x52 0x92 0x96 0 56 0 57 0x97 0x55 0 9 0 5 0x5D 0x9D 0 5 0 9 Ox9E 0x5E 0x5A 0 9 0 9 Ox5B 0x99 0x88 0x48 0x49 0x89 Ox4B 0 8 Ox8A 0 4 Ox4E 0 8 0 8 Ox4F 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 OxFF low byte of CRC initialized unsigned ulndex will index into CRC lookup table while usDataLen pass through message buffer uIndex uchCRCLo puchMsgg calculate the CRC uchCRCLo uchCRCHi auchCRCHi uIndex uchCRCHi auchCRCLo ulndex return uchCRCHi lt lt 8 uchCRCLo OxCl 0 0 0 0 0 1 0 0 0 1 1 0 0 0 0 0 1 0 1 0 0 0 1 0 0 0 0 0 81 0 5 0 09 0x1D OxD1 0x35 0 9 OxED Ox21 0x65 0 9 OxBD 0x71 0x95 0x59 0x4D 0x80 0x81 0x80 0x80 0x81 0x80 0x81 0x81 0x80 0x80 0x81 0x81 0x80 0x81 0x80 0x80 0x40 OxC4 0x08 0 1 0 0 34 0 8 OxEC 0x20 0x64 0 8 OxBC 0x70
16. 43 99 63 4 04 EOT End of Transmission 36 24 5 68 44 D 100 64 d 5 05 ENQ Enquiry 37 25 69 45 101 65 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 2C 76 4 L 108 6C 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 6E 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 U 117 15 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 1 56 38 8 88 58 120 78 x 25 19 End of Medium 57 39 9 89 59 79 y 26 LA SUB Substitute 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
17. 8 06 9 eq Programming 3 PROGRAMMING Next the SCAO6 servo drive parameters related to the Modbus RTU communication will be presented 3 1 SYMBOLS FOR THE PROPERTIES DESCRIPTION RW Reading and writing parameter AC Parameter visible on the HMI only when the corresponding accessory is connected P00650 SERVO DRIVE ADDRESS IN THE SERIAL COMMUNICATION 1 RS232 P00656 SERVO DRIVE ADDRESS IN THE SERIAL COMMUNICATION 2 RS485 Range 1 to 247 Default 1 Properties RW AC Description It allows programming the used address for serial communication of the equipment It is necessary that each device on the network have a different address from one another The valid addresses for this parameter depend on the protocol programmed on the servo drive 54 1 WEGTP Valid addresses 1 30 00654 00660 2 Modbus RTU gt Valid addresses 1 to 247 P00652 BIT RATE SERIAL 1 RS232 P00658 BIT RATE SERIAL 2 RS485 Range O 4800 bits s Default 1 1 9600 bits s 2 14400 bits s 3 19200 bits s 4 24000 bits s 5 28800 bits s 6 33600 bits s 7 38400 bits s 8 48200 bits s 9 48000 bits s 10 52800 bits s 11 57600 bits s Properties RW AC Description It allows programming the desired value for the baud rate of the serial interface in bits per second This rate must be the same for all the devices connected to the network 8 06 10 Programming
18. Motors Automation Energy Transmission amp Distribution Coatings Modbus RTU SCAO6 User s Manual EGG et Modbus RTU User s Manual Series 5 6 Language English Document Number 10001625775 00 Publication Date 12 2012 Contents CONTENTS CONTENTS sa 3 ABOUT THIS 5 ABBREVIATIONS AND 5 NUMERICAL 5 indian 24442148 5 6 22284444 5 5 1 INTRODUCTION TO SERIAL 6 2 NETWORK 7 2 1 EXPANSION AND COMMUNICATION RS232 AND RS485 ECO1 MODULE 7 2 2 RS 232 Cidade
19. TION 11 00663 WATCHDOG 5 1 12 00664 SAVE PARAMETERS NON VOLATILE 12 00667 SAVE ON 6 12 4 MODBUS 14 4 1 TRANSMISSION 14 4 2 MESSAGE STRUCTURE FOR RTU 14 4 2 1 OR 14 4 2 2 COG 14 4 2 3 14 4 2 4
20. bus RTU Network Slave Mode Table 5 1 Modbus RTU Memory Map Parameter number Modbus data address Decimal 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 7 All the parameters are treated as holding type registers Depending on 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 t 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 markers word or float can also be accessed using the Modbus RTU interface Those markers are used mainly by the SoftPLC function available for the SCAO6 Refer to the So
21. e 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 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 8 06 14 Modbus RTU Protocol 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 considered invalid because the servo drive will discard the bytes already received and will mount a new telegram with the bytes that w
22. ere 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 Tasx Thetweenbytes Tasx Transmission Signal Time T11 bits Telegram Table 4 1 Communication rates and the time periods involved in the telegram transmission Thi vits Time for transmitting one byte of the telegram Thetweenbytes Time between bytes T3 5x Minimum interval to indicated beginning end of a telegram 3 5 x T11bits SCAO6 15 Operation in the Modbus RTU Network Slave Mode 5 OPERATION IN THE MODBUS RTU NETWORK SLAVE MODE The 5 6 servo drive has the following characteristics when operated in Modbus RTU network Network connection via RS485 serial interface Address communication rate and byte format defined by means of parameters It 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 SCAO6 the parameters have been defined as being holding type registers In order to access those data the following services or functions have been 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 t
23. error is detected Table 3 1 Options for parameter PO662 2 Description O Cause Alarm It just indicates alarm 1 Cause Fault Instead of alarm a communication error causes a fault on the equipment and it is necessary to reset the faults so as to return to normal operation 2 Execute STOP The alarm will be indicated together with the execution of the STOP command It is necessary to reset the faults or disable the drive for the servo to exit this condition disable command SCAO6 11 Programming The followings events are considered communication errors Serial Communication RS232 RS485 Alarm AO0128 Fault 00028 timeout of the serial interface P00663 WATCHDOG SERIAL Range 0 0 to 999 0s Default 0 0 Properties RW Description It allows programming a time for the detection of the communication error via serial interface 1 In case the servo drive does not receive valid telegrams for a period longer than that adjusted in this parameter it will be assumed a communication error occurred the alarm A128 will be displayed on the HMI or fault F228 depending on the settings on P0313 and the action programmed on P0313 will be executed After energized the servo drive will begin counting this time from the first valid telegram received The value 0 0 disables this function P00664 SAVE PARAMETERS IN NON VOLATILE MEMORY Range O Parameter is not saved in non volatile memory Default
24. es Example reading of basic information in sequence starting from the object 02h from a SCAO6 at address 1 Field O Numberofobjcts 0 12 0200 1 00000000 1 7 0 1 In this example the value of the objects was not represented hexadecimal but using the corresponding ASCII characters instead E g for the object 02h the value V1 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 8 06 20 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 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
25. 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 Initial register address 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 8 06 18 Detailed Description of the Functions Example writing of 2000 rpm as the speed reference P0121 for the slave at address 3 Address 08h 1 byte Initial register address 121 0079h 2 bytes Value for parameter O7DOh 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 Example writing of the digital inputs functions 01 and 2 equal to 4 4 and 10 respectively of a slave at address 15 Address 15 OFh 1 byte Initial register address 300 012Ch 2 bytes Value for the fist parameter 4 0004h
26. ftPLC Manual for the description of those markers as well as for the addresses via Modbus SCAO6 17 Detailed Description of the Functions 6 DETAILED DESCRIPTION OF THE FUNCTIONS A detailed description of the functions available in the SCAO6 servo drive 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 5Fh Refer to the SCAO6 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 Address 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
27. he 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 5 06 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 illustrates the parameters addressing which be accessed as holding type register Functions used to access SoftPLC data SCAO6 16 Operation in the Mod
28. le with DB9 female connectors 10191117 Length 10 meters Other cables however be found on the market commonly referred to as null modem or mounted as desired for installation 2 2 4 Connector Pin Assignment The connection for the RS232 interface is available via connectors XA121 and XA122 using the following pin assignment SCAO6 7 NETWORK CONNECTIONS Table 2 1 Connector pin assignment 85232 121 2 Function RX_232 7 232 RTS E SRS A Table 2 2 Connector pin assignment for 5232 122 Function Reserved 232 RTS Ground 23 RS485 2 3 1 Indications LED LA 122 indicates lights when there is data transmission by the RS485 communication 2 3 2 Characteristics of RS485 interface Interface follows the EIA TIA 485 standard t can operate as a slave of the Modbus RTU network It allows communication using rates from 9600 to 57600 Kbit s Galvanically insulated interface and with differential signal providing more resistance against electromagnetic interference It allows the connection of up to 32 devices to the same segment A larger number of devices can be connected with the use of repeaters Maximum bus length of 1000 meters 2 3 3 Connector Pin Assignment The connection for the RS485 interface is available via XC1 connector using the following pin assignment Table 2 3 Connector pin assignment for RS485 XA121 Function 232 RTS
29. ments 2 Version MODBUS Application Protocol Specification December V1 1b MODBUS ORG 28th 2006 MODBUS Protocol Reference Guide June 1996 MODICON MODBUS over Serial Line December 20th 2006 V1 02 MODBUS ORG In order to obtain this documentation consult MODBUS ORG which is nowadays the organization that keeps publishes and updates the information related to the Modbus protocol SCAO6 5 Len Introduction to Serial Communication 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 RS232 and RS485 serial interfaces available for the product will be presented as well as the protocols for the use of those interfaces 8 06 6 NETWORK CONNECTIONS 2 NETWORK CONNECTIONS In order to allow the serial communication the servo drive SCAO6 it s necessary to use the expansion
30. 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 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 SCAO6 21 weg Faults and Alarms Related to the Modbus RTU Communication 7 FAULTS AND ALARMS RELATED TO THE MODBUS RTU COMMUNICATION A00128 F00028 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 longe
31. r than the programmed in POO663 Working The parameter P00663 allows the programming of a period during which the slave must receive at least one valid telegram via the RS 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 400128 or the fault 0028 depending on the P00662 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 POO663 Disable this function in POO663 SCAO6 22 Appendices APPENDICES APPENDIX A ASCII TABLE Table 1 1 ASCII Characters Dec Hex Chr Dec Hex Chr Dec Hex Chr Dec Hex Chr 0 00 NUL Null char 32 20 Sp 64 40 8 96 60 1 01 SOH Start of Header 33 21 65 41 97 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
Download Pdf Manuals
Related Search