partlow_使用说明书手册_datavu7_modbus.pdf

DataVU7-InterfaceManualModbus

59494

Contents

1Introduction5

1.1Preface5

1.2Typographicalconventions6

1.2.1Warningsigns6

1.2.2Notesymbols6

1.2.3Numbertypes6

2Generalinformation7

2.1Targetgroup7

2.2Interfaces7

2.3Systemprerequisites7

3Connectingtheinterface9

3.1Connectionposition9

3.2RS23211

3.3TogglingbetweenRS232andRS48511

3.4Configurationoftheserialinterfaces12

3.5ConfigurationoftheEthernetinterface13

3.5.1Parameters13

4Modbusprotocoldescription15

4.1Master-Slaveprinciple15

4.2Transmissionmode(RTU)15

4.3Timingofthecommunication16

4.4StructureofaModbustelegram17

4.5Deviceaddress18

4.6Functioncodes18

4.6.1Readnbit19

4.6.2Readnwords20

4.6.3Writeonebit21

4.6.4Writeoneword22

4.6.5Writenwords23

4.7Transmissionformat(integer,float,doubleandtextvalues)24

Contents

4.8Checksum(CRC16)27

4.9Errormessages28

4.9.1Modbuserrorcodes28

4.9.2Errormessagesforinvalidvalues29

4.9.3Errorcodesasintegerreturnvalues30

5Serialprotocoltypes35

5.1Modbusslave35

5.2Modbusmaster38