how to zero the values that are greater than 0 at time 0?

[leelu]

Hello, New user,

I would like to know how to zero values that are greater than 0 at time 0.  I am totalizing gas flow and understand how not to add the negative numbers but am unsure about the positive numbers at 0 flow.  I hope I have explained this good enough.

Thank you,

Lisa

[Ryan.S]

Which object do you use to totalize the gas flow?

If you use Accumulator, its "reset" parameter can zero the value.

Or you can give a simple example to show what you have done and what you want to do.

[leelu]

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Which object do you use to totalize the gas flow?

If you use Accumulator, its "reset" parameter can zero the value.

Or you can give a simple example to show what you have done and what you want to do.

Ryan Shi

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Hello Ryan, thank you for your response,

I am using the integral object to totalize the gas flow.  The INPUT to the integral I use an expression to make values that are less than zero become a zero.  It's when the values are registering as a value greater than 0 that should be 0 are being totalized when they shouldn't.  ie: during no flow.  How do I calibrate the system?  My system consists of KepServer and I am using a SixNet Ethertrak IO module, analog inputs.

Thank you,

Lisa

[Ryan.S]

I don't understand why the value which should be 0 is actually greater than 0.

How do you determine that the value should be 0, such as no flow, even if the value is greater than 0?

[leelu]

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I don't understand why the value which should be 0 is actually greater than 0.

How do you determine that the value should be 0, such as no flow, even if the value is greater than 0?

Ryan Shi

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Hello Ryan,

The system itself may have an offset of 0.1 V which in the program is related to flow.  I do not wish to add this .1 as flow.  I want to beable to reset the values to 0 and then when there is flow, to add the flow.   If you purchase a program from some vendors you can zero the channel, that is my goal.  I want this to be automatic when a switch is pressed.  Such as:  for 20 seconds, average channel, and use that value as 0 flow then add flow??   I was told averaging may work??

Thank you again,

Lisa Williamson

[Ryan.S]

If you are sure that if and only if the value is 0.1 or below 0.1, the flow is 0, it's easy to zero it. 

But if the condition is not definite, for example, when the value is 0.1, but the actual flow may not be 0, how can we know whether we should zero it or not?

I think the question is not how to zero it, but it is when to zero it.

[leelu]

Hello Ryan,

Thank you for your response.  I guess its both questions then.  When and how?  Is it possible?

Thank you,