modbus RTU protocol datatypes

[unclebump]

Look at page G-6 for the address ranges. 40001 gives you channel zero data value. In the starting address field put in a value of 1. Labview does not need the 40000 value. You might need to change the setting for Zero based addressing. Does advantech have a demo program you could use to test your wiring?? you could also use portmon(http://technet.microsoft.com/en-us/sysinternals/bb896644.aspx) to watch the serial data and compare to your labview commands. You could set the quantity to 8 to read all of the inputs. There could be some parameters that you need to set inside the adam unit to make it talk modbus.

[shubhlaxmi22]

Hello Sir,

               I am attaching my block diagram vi.My 4019 device has thermocouple input.Adam.net utility software shows me 24 degree celcius.how could i get this reading using labview?

[shubhlaxmi22]

Thanks for reply.cal u tell me how to convert decimal value into degree celcius?Labview  shows 1965 value of thermocouple hardware as input in registers.

 i want to convert it into degree celcius.

                 Advantech software shows 1965 in modbus part and 24 degree celcius in channel setting.

[unclebump]

Use the portmon program to capture the datastream transmitted by the Adam .net utility program for a few reads. Then post this hex data so we can decode the modbus commands. Then run the labview program and capture the hex code with portmon. Post this data and we'll see what is different.

[unclebump]

Look at appendix B for the data range calculations. It depends on the type of thermocouple you are using.

[shubhlaxmi22]

Can u send me any example vi.i am not getting totally what should i do in labview?

[unclebump]

Download the llb file that I put in this thread,

http://forums.ni.com/ni/board/message?board.id=170&message.id=144504&requireLogin=False

[shubhlaxmi22]

I have download that file but there is no conversion of degree celcius.Am i right that register value is device input value?if i am right then how to convert 4 digit value to degree celcius.

[unclebump]

What type of thermocouple do you have connected and what is the termperature range?? J,K,T,, Each type has a different temperature range and this will change the interpretation of the modbus values. You labview program will need to scale the modbus reading based on your temperature ranges. It is really info that advantech should provide in their engineering info for the module. How do you have the module configured??

-Engineering Units

-Percent of FSR

-Twos complement hexadecimal

-Ohms

 Might be time to talk with someone at Advantech.

[shubhlaxmi22]

Thanks For reply,I am using K type thermocouple(0 to 1390 range).i dont know which type of unit configured in module?can u explain me about all four datatypes.

 I am sending u attachment of device input.one is channel setting and modbus.