I/O and Dataloging DSC MODULE

[Probo]

Morning all..

I'm now using LV 2009 with DSC Module..

now i just trying to develope an HMI sistem, just for monitoring purpose..

can anyone help me to explain

- How did the shared variable work, i have created Modbus I/O server, then how can i read data from a real Modbus Data from PLC.?

  do the Modbus will appear in the network like the I/O server then we binding to the data than want we colect or how? or we just create the I/O server then

  modbus automaticly binding the data to the I/O server that we have made? or how???

- In LV 2009, how can i make a dataloging system.. do I need to create ODBC from Citadel first, or it already exist.. if I need to create this, why the Citadel didn't

  appear in create data base?? 

thankyou..

[Kareem_W.]

Hi Probo,

Please reference the links below for information on logging data using DSC:

1. Logging Data with National Instruments Citadel

http://zone.ni.com/devzone/cda/tut/p/id/6579

2. Data Logging Options Using the LabVIEW DSC Module

http://zone.ni.com/devzone/cda/tut/p/id/12525

There is also some good Modbus example code in the LabVIEW Example Finder. This code has great notes that explain the coding logic. To find these, navigate the following path in LabVIEW:

Open LabVIEW >> click the "Help" menu >> click "Find Examples"

Once in the LabVIEW Example Finder, click on the "Search" tab and type "modbus". There are two examples that show how to communicate using the Modbus protocol, "Modbus Fundamentals" and "Modbus Simulator". The VIs in these two project communicate using the modbus protocol.

Regards,

[Probo]

Hi Kareem..

I already find the Modbus example..

Both of "Modbus Fundamentals" and "Modbus Simulator" have each I/O server, one as Slave and other as device..

But I still confuse how it work, there are no binding variable between them, and how the "modbus device" can acess data from "modbus slave"..

Can U help me to explain how it work, I have read help in LabView over and over but I still didn't understand.??

[Kareem_W.]

When you create a shared variable using the modbus IO server, you are binding to a specific address on the device. The address range is based on the type of data that you are trying to retrieve. This can be found in the manual for your PLC. In order to link two variables, you need to bind the Modbus Master shared variable (in the master project) to the same address as the Modbus Slave shared variable (in the slave project). Once you do this, the software takes care of the rest.

As an example, let's say that you have a temperature value that you'd like to import into LabVIEW and this data is being stored in address location 400000 on you PLC. You would first have to create a shared variable library in the master project with a variable bound to address 400000. You would then have to do the same thing in the slave project with a shared variable bound to 400000 as well. Once VI is run and the libraries are deployed, as the PLC updates the value in address 400000 this value is reflected by the shared variable in the master library, which then passes the same value to the shared variable in the slave library. Remember, they are both tied to the same address.

Regards,

[Probo]

Thankyou for your explanation Kareem..

I just tried to make what U said, I atthacet it with picture in a .doc file..

Please review, do my step is correct..

do I can read the data from PLC with have address 400001 automaticly when I conect to the PLC??

[Probo]

Thankyou for your explanation Kareem..

I just tried to make what U said, I atthaced it with picture in a .doc file..

Please review, do my step is correct..

do I can read the data from PLC with have address 400001 automaticly when I conect to the PLC??

[Probo]

Thankyou for your explanation Kareem..

I just tried to make what U said, I atthaced it with picture in a .doc file..

Please review, do my step is correct..

do I can read the data from PLC with have address 400001 automaticly when I conect to the PLC??

[Probo]

Thankyou for your explanation Kareem..

I just tried to make what U said, I atthaced it with picture in a .doc file..

Please review, do my step correct..?

do I can read the data from PLC with have address 400001 automaticly when I conect to the PLC??

[Kareem_W. · Accepted solution]

In the bottom window of page 2, make sure that you click "Add Range" in the middle panel and not "Add". This is because you must first provide the range that your address falls within, then specify the actual address. This ensures that the data type is correct, because each range contains specific data types.

[Probo]

Thankyou for Your answer Kareem..^_^