Kurz 454FTB - Modbus

KurzHardwareReferenceGuide3–4
SerialCommunications
Modbus
Important DonotconnectaB‐SeriesdevicetoaModbusnetworkuntilitisproperly
configured.
Modbusisanetworkcommunicationprotocolthatcommunicatesusingamaster‐slave
technique,inwhichonemasterdeviceinitiatestransactionsorqueriestoslavedevices.Theslave
devicessupplytherequesteddatatothemasterorperformtheactionrequestedinthequery.
ModbusRTUisthedefaultcommunicationprotocol,although
ModbusASCIIisavailable.
The B‐Seriescanonlycommunicateasaslave devicetoamasterdevice.
RS‐485canbeusedviatheModbusprotocoltocommunicatewithB‐Seriesdevices,butRS‐485
mustbeconfiguredashalf‐duplexinapoint‐to‐pointormulti‐dropnetwork.
Whenusedina
multi‐dropnetwork,eachslavedevicemusthaveauniquedeviceaddresswithinthenetwork.
Theindividualslavedeviceaddresscanbeassignedintherangeof1to247.
ForModbusserialRTU,theCOMportnumbersandavailableCOMportoptionsarebasedon
hardwareand
softwareconfiguration.YoumustuseaUSB‐to‐RS‐485convertertocommunicate
viaModbus.Acommunicationsportoptionappearsonlywhenthereisaphysicalportora
hardwaredeviceisattachedtothecomputerandadevicedriveridentifiesitasaCOMport.Refer
toyourconverter
documentationforCOMportidentificationinformation.See“Identifyingthe
COMPort”foradditionalinformation.
Identifying the COM Port
Ifthedrop‐downlistfortheCOMPortfielddoesnotprovideanidentifiablename,open
WindowsDeviceManager.Youcandothisbyusingoneofthefollowingmethods:
• SelectControlPanel→DeviceManager.
• OpentheWindowsComputerManagementwindowandclickDeviceManager.
• ForWindowsXP,chooseStart→Run,typingdevmgmt.mscintheOpenfieldoftheRun
dialogbox,andpress Enter.
• ForWindows7andWindows8,chooseStartandtypeDeviceManagerinthesearchfield.
Youcanselectitwhenitappearsasanoption.
IntheDeviceManagerwindow:
1> ExpandPorts(COM&LPT).
IfyouinstalledtheKurzUSBdriverandaB‐Seriesdevicewithabarcodelowerthan
C51938iscurrentlyconnected,itwillbelabeledasKurzUSB‐HID‐>COMdevice.
IfyouinstalledtheFTDIUSBdriverandaB‐Seriesdevicewith
abarcodeC51938or
higheriscurrentlyconnected,itwillbelabeledasUSBSerialPort(COM#).
IfaUSB‐to‐RS‐485adapterisused,itsnamemayreferencethemanufacturer.
2> Toverifytheportnumber,unplugtheUSBconnector,andthenplugitbackin.
TheCOMportentrythatdisappearsandreappearsis theportusedfortheKurzdevice.