We are trying to connect to 3 plc stations wired through an ethernet network. The three plc's are to be connected to a switch/hub. The port 1 of the hub obviously connects to the PC. The PC hosts the labview program.
Q1. The variables in Labview - what is the correct way to publish them as network variables wherein one may access them globaly?
Note: Presently,the approach we are using is to create an NI OPC server wherin we are defining the variables as per our requirement. Thereafter the process of using them in a project is confusing. Using the Modbus protocol, we are:
creating a new I/O server in the project, locating the opc server we made in NI opc server & including it in the project.
We thought that at this stage, all the defined variables should automatically get included with their tag names defiened in NI OPC server. This does not happen nor can one drag the variable onto the new VI.
Instead we have to again, create a new variable & uses the PSP URL check box. Then we have to browse for the particular variable. Once this is done then the variable may be dragged on to VI & works well.
Is this the right way to do things? I's almost sure it is'nt.
Q2. The scaling option in the NI OPC server does'nt seem to be too flexible. How may I use it to scale, say, a variable 0~3000 counts of raw data to a 0~30bar value?
Monti
Vaishakh
