How to create custom calculated channel in VT?

[GintsK]

Hi, VEMS users!
My current need is to create new channel: [(GPSspeed/RPM)*constant]. Is it possible and how?

Gints

[gunni]

I belive it is not possible, I have a host of channels I´d like
Like POWER and TORQUE

[GintsK]

Probably they are defined in .ini file...

[gunni]

I mean channels where you apply numerous math to one or more input channels to recieve a output.

Is this possibly in .ini files?

[VEMS]

http://vems.hu/vt/help/gauges/customvaluegauge.html

Regards, Dave

[GintsK]

OK... thanks!
My expression then is

"%.3f km/h",gpsSpeed*35.084/rpm

It returns something like gear ratio - should be exact value until gear is changed or clutch pressed.
But due to nature of incoming signals output becomes noisy.

Next - it would be nice to get average from e.g. last 200 samples.
May be someone can help me to create such expression?

Is there way to get freshly created channel in datalog?

Gints

[VEMS]

Since the custom value gauge is using already available logged channels as inputs, the custom gauge should also be available when replaying a log.

Regards,  Dave

[gunni]

Can it be selected as a channel in the log viewer ?

I made a math channel that creates road speed from tyre size, gear ratio and diff ratio, called it a unique ID but cannot select that ID to create new symbol as it´s not available, the other available custom Id are also not available as selectable symbols.

This would be one of the best possible features if this can be made to work in log viewer.

Thanks Dave.

EDIT .
Ideally being able to make numerous new channels and use them in other math channels would be ideal. Also applied filtering and
if possible "last value" usage.

[GintsK]

Since the custom value gauge is using already available logged channels as inputs, the custom gauge should also be available when replaying a log.

Regards,  Dave

Yes it persists in log replay, but it does not help to read average. Graph line in logviewer would be much more helpful.

[fphil]

It returns something like gear ratio - should be exact value until gear is changed or clutch pressed.
But due to nature of incoming signals output becomes noisy.

Next - it would be nice to get average from e.g. last 200 samples.
May be someone can help me to create such expression?

Why not a set of if applied on the output value which selects the right case/gear ?

[GintsK]

Sorry??

[fphil]

r= noisy result gear ratio calculus
ei= theoritical gear ratio value for gear i

the set of if is per example

if 0.8*e1< r < 1.2*e1 then gear is gear number one
if 0.8*e1<r<....  then gear is gear number 2
etc...

of course you can do better intervals to avoid ghost cases.

[GintsK]

My purpose is not to determine gear, but exact gear or transmission ratio necessary for following performance measurement. Error here means error later.

Gints

[gunni]

It´s also excellent to detect slipping clutches or tyres.

I do agree that filtering would be excellent.

[fphil]

Alright transmission ratio.
You may do schedule filter or dead band filter as above, with 6, ..., 12 possible transmission ratios. This quantification could filter part of the noise or may easier the data analysis.