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Version 4.0 

 

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1. Communication Functions 

1.1 General   

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MV-D94 provides a communication function by RS-485 interface, by which it can 
transmit and receive data to and from host computer, programmable controller, 
graphic display panel, etc. 

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The communication system consists of master station and slave stations. Up to 
255slave station can be connected per master station. 

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In order that the master station and slave station can communicate, the format of 
the transmit/receive data must coincide. For the MV-D94, the format of the 
communication data is determined by the MODBUS protocol (RTU mode). 

z

 

Please use an RS-232C

RS-485 converter in case of designating a personal 

computer or other devices which have an RS-232C interface as a master station. 

 

Содержание SetPro MV Series

Страница 1: ...ration Method 5 5 MODBUS COMMUNICATION PROTOCOL 5 1 General 6 5 2 Composition of Message 6 5 3 Response of Slave Station 7 5 4 Function Code 8 5 5 Calculation of Error Check Code CRC 16 8 5 6 Transmission Control Procedure 9 6 DETAILS OF MESSAGE 6 1 Read out of Word Data Function Code 03 11 6 2 Read out of Read Only Word Data Function Code 04 12 6 3 Write in of Word Data 1 word Function Code 06 13...

Страница 2: ... of master station and slave stations Up to 255slave station can be connected per master station z In order that the master station and slave station can communicate the format of the transmit receive data must coincide For the MV D94 the format of the communication data is determined by the MODBUS protocol RTU mode z Please use an RS 232C RS 485 converter in case of designating a personal compute...

Страница 3: ... 500m max Transmission speed 2400 4800 9600 19200 selectable Start bit 1 bit Data length bit 8 bits Parity bit None Data format Stop bit 2 bits Transmission code HEX value MODBUS RTU mode Error detection CRC 16 bits Isolation Functional isolation between transmission circuit and others with stand voltage 500V AC A typical MODBUS protocol character is shown below 1 2 3 4 5 6 7 8 9 10 11 Start bit D...

Страница 4: ... TX 14 TX 3 2 Wiring z Use twisted pair cables with shield Recommended cable UL2464 UL2448 etc z The total extension length of the cable is up to 500m A master station and up to 255 units of the MV D94 can be connected per line z Both ends of the cable should be connecting with terminate resistors 100Ω 1 2W z The shield wire of the cable should be grounded at one place on the master station unit s...

Страница 5: ... different from each other 4 1 Set Items The parameters to be set are shown in the following table Set them by operating the front panel keys Parameter Item Value at delivery Setting range Remarks Transmission speed 9600 2400 4800 9600 19200 Data length 8 bits Fixed can t be changed Stop bit 2 bit Fixed can t be changed BAUD Parity setting None Fixed can t be changed Set the same communication con...

Страница 6: ...multaneously for approximately 5 seconds to get level parameter SET 5 seconds TYPE Press SET key simultaneously for approximately 5 seconds to get level parameter SET Press SET key to go into level SET ADDR Press SET key repeatedly until ADDR is display or ADDR 12 Press or key to setting ADDR 12 SET BAUD Press SET key again to select next parameter BAUD or BAUD 9 6K Press or key to setting BAUD 9 ...

Страница 7: ... sends in this order The allowable character transmitted for all fields are hexadecimal 0 9 A F RTU mode framing START ADDRESS FUNCTION DATA CRC CHECK END T1 T2 T3 T4 8 BITS 8 BITS N 8 BITS 16 BITS T1 T2 T3 T4 In the following each field is explained 1 Start In RTU mode messages start with a silent interval of at least 3 5 character times This is most easily implemented as a multiple of character ...

Страница 8: ...ssage errors change in bit in the signal transmission On the MODBUS protocol RTU mode CRC 16 Cyclical Redundancy Check is applied For CRC calculation method refer to section 5 5 6 End Following the last transmitted character a similar interval of at least 3 5 character times marks the end of message A new message can begin after this interval 5 3 Response of Slave Station 1 Response for normal com...

Страница 9: ...lation of Error Check Code CRC 16 CRC 16 is the 2 bytes 16 bits error check code From the top of the message address to the end of the data field are calculated The slave station calculates the CRC of the received message and does not respond if the calculated CRC is different from the contents of the received CRC code A procedure for generating a CRC is 1 Load a 16 bits register with FFFF hex all...

Страница 10: ...re vacant status between the end of response message reception and beginning for next command message sending same as in 1 1 1 5 For ensuring the safety make a confirmation of the response message and make an arrangement so as to provide 3 or more retries in case of no response error occurrence etc Note The above definition is for most unfavorable value For ensuring the safety it s recommended the...

Страница 11: ... of 1 command message is smaller than 22 bits time 2 Response of this instrument After a frame detection 22 bits time or more vacant status this instrument carries out processing with that frame as a command message If the command message is destined to the own station a response message is returned Its processing time is 1 to 10ms depends on contents of command message After sending a command mes...

Страница 12: ... 2 bytes 2 bytes Maximum word number 7E Response message composition Address Function Byte Number Word Data CRC 16 01 FF 03 02 FC Low order byte High order byte 1 byte 1 byte 1 bytes N bytes 2 bytes Byte number Word number 2 2 Message transmission example The following show an example of reading the Set point Value 1000 from address No 1 controller Command message composition Address Function Star...

Страница 13: ...1 byte 1 byte 2 bytes 2 bytes 2 bytes Response message composition Address Function Byte Number Word Data CRC 16 01 FF 04 02 FC Low order byte High order byte 1 byte 1 byte 1 byte N bytes 2 bytes 2 Message transmission example The following show an example of reading the Process Value 27 from address No 1 controller Command message composition Address Function Starting Address Word Number CRC 16 0...

Страница 14: ... composition Address Function Starting Address Word Data CRC 16 1 FF 06 0xxx 0xxx Low order byte High order byte 1 byte 1 byte 2 bytes 2 bytes 2 bytes 2 Message transmission example The following show an example of writing the Set point Value to address No 1 controller Command message composition Address Function Starting Address Word Data CRC 16 01 06 0000 01F4 89DD Response message composition A...

Страница 15: ...and Pb proportional band 100 0 will be transfered to 03E8 hex Index code Some parameters value are set by index code For example to change the unit to via communication The data value would be 0017 hex Code English Code English Code English Code English 00 J 0F ENG 1E 9 6K 2D 1101 01 K 10 0000 1F 19 2K 2E 1110 02 T 11 000 0 20 0000 2F 1111 03 E 12 00 00 21 0001 30 HI 04 B 13 0 000 22 0010 31 LO 05...

Страница 16: ...10 HYST 0 2000 000A 40011 A1HY 0 2000 000B 40012 A2HY 0 2000 000C 40013 A3HY 0 2000 000D 40014 LOCK 0000 1111 000E 40015 TYPE J K B R S T E N C DPT JPT LINE English code 000F 40016 UNIT ENG English code 0010 40017 DP 0000 000 0 00 00 0 000 English code 0011 40018 ACT REV DIR English code 0012 40019 LOLT 1999 9999 0013 40020 HILT 1999 9999 0014 40021 FILT 0 0 100 0 0015 40022 A1FU None Hi Lo dif H ...

Страница 17: ...dy Lath St La T End English code 001B 40028 ADDR 0 255 0 001C 40029 BAND 001D 40030 CH01 0 2000 001E 40031 CL01 0 2000 001F 40032 RTSH 0 3000 0020 40033 RTSL 0 3000 0021 40034 MR 0 0 100 0 Word data read out only Function code 04 Data Address PM Designer Parameter Contents Unit 1000 34097 PV Process value PM Designer Driver Modicon Corp Modicon 984 Device Slave RTU ...

Страница 18: ... instruments and connection distance are as specified Whether communication conditions coincide between the master station host computer and slave station MV D94 Transmission speed 2400 bps 4800 bps 9600 bps 19200 bps Address 01 FF master and slave station must be match Whether send receive signal timing conforms to Section 5 4 in the manual Whether more than one instrument connected on the same t...

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