Teledyne 9060Z Manual

Open as PDF

next previous

Model9060ZManual



61





APPENDIX4,MODBUS™

TheTeledyneAnalyticalInstruments9060ZtransmitterhastheabilitytoworkasaModbusslavenode

onserialRS‐232or3‐wireRS‐485viaRTUmodetransmissions.Byaccessinginformationstoredinthe

inputandholdingregistersitispossibletoaccessruntimevariables,alarmconditionsandmodifythe

deviceconfiguration.

The implem

entation of the Modbus protocol is limited to the specific command set relevant to

reading and writing register variables. Attempting to send unrecognised commands will result in

appropriateerrorresponses

MODBUS™FunctionsSupported:‐

0x03:ReadHoldingRegisters

0x04:ReadInputRegisters

0x06:WriteSingleHoldingRegister

0x08:(returnquerydata–forloopbacktesting)

0x10:WriteMultipleHoldingRegisters

0x16:MaskWriteHoldingRegister

0x17:Read/WriteMultipleHoldingRegisters

0x2B:EncapsulatedInterface(readdevice

information)

0x41:SpecialInstructionFunction

SerialConfiguration

The serial configuration for the slave device is accessed in the Commissioning menu of the

transmitter.Defaultsettingsarehighlightedinbold.

BaudRate 9600,19200,38400,57600

Parity Even,Odd,None

StopBits 1

Interface RS‐485,RS‐232

All holding register addresses contain a single 16 bit value, howeversome variables span multiple

holdingregisterstoyieldasingle32bitvariable.

Whenreadingregistervaluesbeawarethatthebyteorderofdatawithinregistersmaydifferfrom

thatofthetargetsystem.

ModbusProtocol

Themodbusoverseriallineprotocoldefinesamessagingsystemformaster/slavecommunications.

Onlyonemasterdevicemaybeconnectedtoanynetworkwithoneorseveralslavenodes.

Inunicastmode,themasterinitiatescommunicationwithaspecificslavenodebysendingarequest

message.Theslaveprocessestherequestandreturnsareplymessagecontainingtherequested

informationoraconfirmationthattherequestwasfulfilled.

ModbusrequestsaretransmittedasaformedrequestframewithaCRCfordataintegritychecking.

The frame for each request and reply type will vary somewhat, but will always have the basic

structuredescribedbelo

w:

1byte 1byte upto255bytes 2bytes

slaveaddress functioncode data checksum

InternalRepresentationofDates&AlarmStatus

Thetransmitterstoresalldatesasanunsigned32bitcountofsecondselapsedsince1‐Jan2004.