Labview addressing for Modbus

[WingFatt]

Can anyone help up here.

I'm using LabVIEW 8.5, i wish to communicate a Transmitter using MODBUS.

the transmitter i'm using here is Micro Motion Transmitter Model: 1700C11ABFEZZZ (from Emerson). 
  
I manage to communicate with the transmitter & only manage to get those Holding Registers, Input Regsisters, but not Floating-Point Register.
The device is having paired floating-point register with 16 bits data rate. eg. for reading Temperature Value, the register is 20251 & 20252.

my problem is when i refer to the NI addressing documentation, there are no Floating-point address that start with "2".

i've tried with various addresses such as F400251, F200251, F20251 and so on, but all i get is "bad quality" connection.

can anyone advice how to communicate with Floating-point address 20251 in LabVIEW?

[WingFatt]

This is the document for Modbus Addressing for the transmitter i'm using.

[WingFatt]

Dear All, i got the following reply from NI technical support. (asean@ni.com)

 ____________________________________________________________________________________________________________

Floating Point Register Pair data type is not supported by Modbus DSC. This is the reason why you can't access it.

Although there isn't any solid foundation, by convention, four data types are available through Modbus; coils, discrete inputs, input registers, and holding registers. Sometimes though, manufacturers tend to add some extra ones to customize the communication for their application, for this case, it was the Floating Point Register Pair.

On these cases though, the most relevant of data are available for two data types to cater to availability issues (if ever their product needs to be interfaced through third-party units, like this scenario).

For this instance,  the Mass Flowrate is available through 20247 (Floating Point Register Pair) and 00002 (Input Register). If you want to access the data through LabVIEW, it can only be done through address 300002.

Again I'm sorry for the very late reply. Please email me if any clarification is needed or if you require something else.

Thanks and Best Regards,
Joshua de la Llana