I used the library (NI Modbus Library 1.2.1) to read and record the value measured by the slaves (temperature, relative humidity, air velocity ...) so I used labview as a master and everything works fine.
after that I used a data logger (ADFweb Modbus logger series HD67324-B2) as succours to read and record the values measured by the slaves every 10 minuts.
I used this data logger to ensure that the values measured results will not be lost if the computer is closed (where the Labview is running).
all what I want is to use labview to download the data recorded by the data logger who works as a master (modbus).
Please see the attached file where there's the data recorded by the data logger. I downloaded using the Software (SW67324).
I want to download the same data using labview.
I could be wrong but it now sounds like this has nothing to do with modbus. The datalogger might use modbus to get its data, but that isn't the protocol used to communicate with the datalogger.
A quick glance at the manual says it uses some sort of serial port and the only obvious way to get data out is through their tool. I'd recommend contacting the manufacturer of the datalogger to see if they have either (a) an API or (b) a list of commands that can be used to grab data from the logger. If they do not, I'd recommend using something like NI I/O Trace (should be installed with NI-VISA and already on your computer) to see if you can figure out what commands they are sending. If the manufacturer won't help you and the I/O trace is too complex to reverse engineer, you may be out of luck.
thank you for you reply Smithd , i ll contact the manufacturer