04-14-2015 10:28 AM
hi , I'm trying to take values from step7 using OPC server, there is no problem sending the values . the only problem is that I can't get the negative values knowing that in OPC server the negative value is seen . when I use an indicator in labview I'll get 4.29 for negative values . I dn't know where is the problem .
04-14-2015 03:29 PM - edited 04-14-2015 03:31 PM
We probably need significantly more information. Can you show us some code?
Do all negative values show up as 4.29, irrespective of their original negative value?
You mention shared variables in the post title? What is the significance?
04-14-2015 04:10 PM
I mean by shared variable , the shared variables created by the OPC server between PLC and labview
as can be seen in OPC server the value of the error is -3.6685 but in the indecator of labeview I get 4.29467296 E+9
04-14-2015 04:10 PM
I mean by shared variable , the shared variables created by the OPC server between PLC and labview
as can be seen in OPC server the value of the error is -3.6685 but in the indecator of labeview I get 4.29467296 E+9
04-14-2015 04:23 PM
That looks like the kind of problem you might have if the endianness was wrong. And are you sure your data is being sent as single precision float and not an integer?
The value 4,294,967,296 is very close (as in right next to) the upper most value for a U32 integer which would be 4,294,967,295.
I would double check the data settings in the OPC server for that variable to be sure the data type and the endianness are set correctly.
04-14-2015 04:33 PM
as it is indicated in the OPC it is in float point 😕 . what doyou mean by endianness ??
04-14-2015 04:36 PM
@riki35 wrote:
as it is indicated in the OPC it is in float point 😕 . what doyou mean by endianness ??
http://en.wikipedia.org/wiki/Endianness
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04-14-2015 04:49 PM
sorry I could not figure out where is the problem although the configuration in OPC is correct 😞