Teledyne 9060Z Oxygen Equipment User Manual


 
Model9060ZManual
61
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APPENDIX4,MODBUS™
TheTeledyneAnalyticalInstruments9060ZtransmitterhastheabilitytoworkasaModbusslavenode
onserialRS232or3wireRS485viaRTUmodetransmissions.Byaccessinginformationstoredinthe
inputandholdingregistersitispossibletoaccessruntimevariables,alarmconditionsandmodifythe
deviceconfiguration.
The implem
entation of the Modbus protocol is limited to the specific command set relevant to
reading and writing registervariables. Attempting to send unrecognised commands will result in
appropriateerrorresponses
MODBUS™FunctionsSupported:‐
0x03:ReadHoldingRegisters
0x04:ReadInputRegisters
0x06:WriteSingleHoldingRegister
0x08:(returnquerydataforloopbacktesting)
0x10:WriteMultipleHoldingRegisters
0x16:MaskWriteHoldingRegister
0x17:Read/WriteMultipleHoldingRegisters
0x2B:EncapsulatedInterface(readdevice
information)
0x41:SpecialInstructionFunction
SerialConfiguration
The serial configuration for the slave device is accessed in the Commissioning menu of the
transmitter.Defaultsettingsarehighlightedinbold.
BaudRate 9600,19200,38400,57600
Parity Even,Odd,None
StopBits 1
Interface RS485,RS232
All holdingregister addressescontain asingle 16bit value,howeversomevariables spanmultiple
holdingregisterstoyieldasingle32bitvariable.
Whenreadingregistervaluesbeawarethatthebyteorderofdatawithinregistersmaydifferfrom
thatofthetargetsystem.
ModbusProtocol
Themodbusoverseriallineprotocoldefinesamessagingsystemformaster/slavecommunications.
Onlyonemasterdevicemaybeconnectedtoanynetworkwithoneorseveralslavenodes.
Inunicastmode,themasterinitiatescommunicationwithaspecificslavenodebysendingarequest
message.Theslaveprocessestherequestandreturnsareplymessagecontainingtherequested
informationoraconfirmationthattherequestwasfulfilled.
ModbusrequestsaretransmittedasaformedrequestframewithaCRCfordataintegritychecking.
The frame for each request and reply type will vary somewhat, but will always have the basic
structuredescribedbelo
w:
1byte 1byte upto255bytes 2bytes
slaveaddress functioncode data checksum
InternalRepresentationofDates&AlarmStatus
Thetransmitterstoresalldatesasanunsigned32bitcountofsecondselapsedsince1Jan2004.