@KPAC wrote:
I've a ge fanuc versamax plc. I am building a data logger in labview. There are two current trasmitters. I dont have any other data acquisition devices other than PLC. How can i access data acquired by PLC and how can i connect it with labview using VISA?
There may be variations between models, but I believe all VersaMax support Modbus and GE's own SNP/SNPX serial communication protocols.
For Modbus communication protocol:
The link
here is a good outline of the different options available. If you really want to limit yourself to the option of using VISA, then it's Items 1. and 2. in Khalid's list that are applicable. You might have to modify some of the free LabVIEW Modbus VIs to suit you needs, but they are useful as examples if you have little experience programming a serial driver.
For SNP/SNPX:
Your options are similar to those for Modbus, except that I'm not aware of any existing free set of LabVIEW VI's for it. With a web search you
might find something (I almost programmed one 10 years ago). The SNP/SNPX protocol is/was well documented in a GE FANUC manual which you could get from them (in 1993 it was GFK-052B "Series 90 PLC Serial Communications User's Manual") so you still can write your own set of VIs.
If you don't really need to limit yourself to using VISA, there are ActiveX and OPC drivers available which use SNP/SNPX that you can find with a web search. And you can see
here that NI's Industrial Automation OPC Server's do include an object for GE Fanuc Versamax via Ethernet. This would not be the cheapest in terms of capital cost though.
Good luck.
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