LabVIEW
Can LabVIEW be used to activate a test device running on a Keyence PLC programmed with Keyence Ladder Logic?
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Giridhar,
Using ActiveX with LabVIEW is pretty easy. All you need to do is put down an automation open.vi and then create a constant for the "Automation Refnum". Then right click on the constant and select "select ActiveX Class". This will allow you to then browse to your application of interest. At this point you now have a reference to the application and can use property and invoke nodes to access the various features of the application.
Of course, this assumes that the application in your zip file registers the ActiveX class on your computer. I looked in the readme and there were directions on using the program, as well as an email address for questions \ suggestions. If you have problems using it, I'd contact that person.
For more information on using ActiveX in LabVIEW see, Using ActiveX with LabVIEW.
Chris C
I think this forum is not the right place to ask these question. There is probably nobody who knows specifics about these ActiveX controls and you would be better of asking these question to the programmer or the distributor you got the controls from. As to why the Property nodes show nothing there are a number of possible reasons: Corrupted file, not registered Active X object, licensing restrictions, etc. The people that created it could probably really help you here.
@Giridhar_Rajan wrote:Hi Chris,Thanks for your reply. I'm able to access only the omron active-x control but not keyence. Is there something wrong with the file or is there some compatibility issue. The property node and invoke node show nothing inside.Regards,Giridhar Rajan
Rolf Kalbermatter
This is always another option. I implemented several VI libraries in the past to access PLCs and PLC alike systems over serial port and TCP/IP directly such as AutomationDirect PLCs, Siemens AS511, Opto22 SnapIO, Haidenhein TNC, etc. However don't underestimate the work this will be. In general if the protocol is documented at least I can get something working in a single day, but until the protocol libraries are so well developed that they can work stable and reliably over days and weeks of uninterrupted communication with the device, you easily spend anything from one week to five or six weeks of development work. The difficulty is usually not to get the communication going, but to get a library that can cope with communication errors by ignoring certain errrors or retrying the operation even before the higher level software gets aware that there might have been a problem at all.
@Giridhar_Rajan wrote:
Rolfk,
Thanks for your suggestion on this. Perhaps i could develop a VI library for myself which could communicate with the keyence PLC and perform all the operations mentioned in the keyence manual. Thanks everybody for your valuable suggestions and help.
Of course if OPC is the only commercially available option and you do need to operate on a RT target for instance there is no other option than to dive in such a driver development. If however your time is limited and you do want a rather reliable operation and can work from a normal Windows computer using an OPC solution will almost always be easier, cheaper and much better for your blood pressure.
Rolf Kalbermatter
