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Why don't I get the exact value back from a PIPoint that I saved?

Question asked by DawidG on Jul 31, 2018
Latest reply on Aug 1, 2018 by DawidG

I have run a couple of tests and the tests always fail.

 

Using the AF SDK, I send PIPoint data, then read them back immediately as a test. The retrieved values are never exactly the same, off by a very small margin.

 

Examples:

Name

Value

Type

Original testValue

15.26

double

val.ValueAsDouble() read from PI

15.260000228881836

double

 

And again

 

Name

Value

Type

testValue

39.07

double

val.ValueAsDouble()

39.069999694824219

double

 

And again

 

Name

Value

Type

testValue

44.19

double

val.ValueAsDouble()

44.189998626708984

double

 

This is the code that sends the data:

this.piServer.UpdateValues(

valuesToWrite,

config.AFUpdateOption,

AFBufferOption.DoNotBuffer);

 

NameValueType
valuesToWrite[0].ValueAsDouble()12.34double

 

After reading it from PI, the value is

NameValueType
val.ValueAsDouble()12.340000152587891double

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