How to do block read when using datasocket?

[SteveChen]

I am going to read a serial of data from AB-Logix using Labview. I am able to link each member to datasocket and read these members one by one. But it's too slow.

Is anyone who know how to do datasocket block read? Is there any other better way? Where can I find some samples? Thanks in advance for your help.

Regards

Steven

[Donald]

Steven,

Andrew_Russell recently has posted a few Datasocket url's that he found worked for block reads/writes of booleans and floats from an AB-PLC5/RSLinx which might be worth trying. You can find them here.

Message Edited by Donald on 03-15-2005 01:15 AM

[SteveChen]

Thank you.

I tried the URL format mentioned in Andrew Russell's message. It didn't work. I think the reason is I do not use RSLinx my application. So I do have RSLinx OPC Server and relative controls. Actually, I am using programming port of AB-Logix to communicate with LabView through datasocket with DF1 protocol.

Is there any other way?

Regards

Steven

[Philip_Courtois]

Hi Steve,

Please let me know what you mean by "it didn't work". Is it the same behavior as before?

[SteveChen]

I am going to read 10 sequential items in a file say N99 from AB-Logix. Currently, I defined 10 items and their aliases in Lookout Protocol Drivers OPC Server 4.5 and connected datasocket to each item and read 10 items one by one in LabView. It works but is too slow.

I tried method mentioned in Donald's reply and set URL to opc://localhost/National instruments.OPCLookoutDrivers/AB1.N99_0,L10, where N99_0 is the alias of N99:0 item. But there is an error saying "OPC item not find" when doing DataSocket Open VI. Maybe, I am not using it properly.

Looking forward to your direction. Thank you.

Best regards

Steven

[Donald]

Steven,

Not all OPC Servers are equal, and not all of them support array/block read-writes. For the AB-Logix, RSLinx (which is an AB product after all) supports them ... but I don't think the AB-Logix object in LPD v4.5 does. Hopefully, I'm wrong.