Proline Promass 83E/F/O Modbus RS485 Operating Instructions

OperationProline Promass 83 Modbus RS4855.5.5 Modbus register addressesEach device parameter has its own register address. The Modbus master uses this register addressto talk to the individual device parameters and access the device data.The register addresses of the individual device parameters can be found in the "Description ofDevice Functions" manual under the parameter description in question.!Note!Fig. 33: Example of how a function description is illustrated notnotin the "Description of Device Functions" manualnot1 Name of the function2 Number of the function (appears on the local display; is not identical to the Modbus register address)3 Information on communication via Modbus RS485 not– Modbus register (information in decimal numerical format) not– Data type: Float, Integer or Stringnot– Possible ways of accessing the function: read = read access via function codes 03, 04 or 23write = write access via function codes 06, 16 or 23Modbus register address modelThe Modbus RS485 register addresses of the measuring device are implemented in accordance with"Modbus Applications Protocol Specification V1.1".In addition to the specification mentioned above, systems are also deployed which work with aregister address model in accordance with the "Modicon Modbus Protocol Reference Guide(PI-MBUS-300 Rev. J)" specification. With this specification, the register address is extended,depending on the function code used. A "3" is put in front of the register address in the "read" accessmode and a "4" in the "write" access mode.FunctioncodeAccesstypeRegister in accordance with:"Modbus Applications ProtocolSpecification"Register in accordance with:"Modicon Modbus ProtocolReference Guide"030423ReadXXXXExample: mass flow = 20073XXXXExample: mass flow = 32007061623WriteXXXXExample: reset totalizer = 64014XXXXExample: reset totalizer = 46401!Note!Response timesThe time it takes a measuring device to respond to a request telegram from the Modbus master istypically 25 to 50 ms. If faster response times are needed for time-critical applications (e.g. batchingapplications), the "auto-scan buffer" is to be used.It may take longer for a command to be executed in the device. The data is not updated until thecommand has been executed. Especially write commands are affected by this!Page 46 • MN0M030Issue/Rev. 0.2 (12/12)