hypertrend trace sloped or stepped?

[jrcamenzind]

Hi,

What determines whether a hypertrend trace goes from point to point (sloped) or whether it only is made up of horizontal and vertical elements (stepped)?  I have seen both of these types of traces on one hypertrend and the difference appears to be data related but what exactly are the conditions?

Thanks,

Joe C.

[Ryan.S]

Can you give a screenshot of these two displays?

[jrcamenzind]

Ryan,

I've included a link that shows what I'm talking about.  The hypertrend in the upper left show data from the ASCII object and the green line is from an expression.  The green line appears stepped while the others appear sloped.  The data from the ASCII object is received  every 2 minutes.  As seen in the hypertrend in the lower left corner, hypertrend waits the 2 minutes (you can see the gap)  then plots a slope.  The green line which is data from an expression is continously plotted, so that any change in value creates a step.  I guess my question is really about trend updates.  What determnines how long before a trace is updated? Can an expression be plotted based on change in data instead of continously?

http://jrcamenzind.googlepages.com/lookout

Thanks,

Joe C.

[Ryan.S]

They are different kinds of data.

For expression or pot, Lookout and Citadel know its real time data. They know when it changes, when it does not change. So, the hypertrend shows the realtime data of it.

But for ASCII or other driver objects, it's different. Lookout polls the device or gets the data at a certain rate, such as you said 2 minutes. During this 2 minutes, Lookout doesn't know the value until next poll or next response from device. So, it has to stop updating and wait for 2 minutes. I think it's reasonable.

[dc@aci]

I have a situation that is related to this.  The hypertrend is displaying flow.  When the flow is 0 it draws a line at the zero mark during this period.  When the flow increases above 0 it draws a diagonal line from the first point where it was 0 to the first non zero value.

I assume this is because Citadel does not store a value to the historical database until it changes more than the resolution setting (set at 0.001).  How can I correct this?

[Mike@DTSI]

The flat areas are where there is no change in data.

Value 0 comes in, two minutes later it is 5. That is an intant jump to 5.  The only way to try an ease this is to poll the data faster.  

0,1,2,3,4,5 would look smoother than 0,5.

Mike

[dc@aci]

Actually...

What happens is that even though the value is zero for lets say, 5 minutes, the trend draws a diagonal line from the first time the flow is zero to the first time it is non zero over the 5 minute period.  It would be correct for it to draw a horizontal line for 5 minutes and then draw a vertical line from the last zero value to the first non zero point.  The poll rate is about 2 seconds.

[Mike@DTSI]

Using the Cursor on the trend, is the diagonal showing increasing values (0,1,2,3,4,5 )?

[dc@aci]

Not sure.  I am not at the field location and no one is there monitoring it right now.  I will have to get back on this one.

My assumption is that the trend is doing this because it not continuously logging the data to citadel during the 5 minute period since the value does not change by the resolution (0.001) amount.  I have seen this before on other projects.  What I would need to be able to do is force the values to be saved to the Citadel everytime Lookout receives a response to a data poll.  This would fix the problem.

[Mike@DTSI]

Are the changes that small? .001?  I have had no issues with logging small values in the past myself, down to .001 resolution as well.

Mike