## Math channels

Forum for discussing PicoScope version 6 (non-automotive version)
Gwill50
Newbie
Posts: 0
Joined: Tue Apr 22, 2014 10:46 am

### Math channels

Does anyone have a formula for rpm?
I am not good at math but would like to have a quick way of determining engine rpm using both ignition events
as well as crank and cam sensors. I tried 60000/freq(a) but gave no joy. I can't seem to find any usable information
for beginners such as myself, and a push in the right direction would be greatly appreciated.

Martyn
Posts: 3464
Joined: Fri Jun 10, 2011 8:15 am
Location: St. Neots

### Re: Math channels

I would suggest you pop across to our Automotive Forum where you will find discussions on this topic

For example http://www.picoauto.com/support/post32131.html
Martyn
Technical Support Manager

wgoettler
Newbie
Posts: 0
Joined: Mon Nov 24, 2014 10:28 am

### Math channels

I am searching for a "math channel" formula to display time diff between rising high A and B.
A is a pulse for an ultrasonic sensor, B is the echo of the sensor.
The time diff between rising A and rising B is the time (way) of the signal.
Now I want to have a curve which represents the passed mm.
Example:

Assumption Signaltime 34,346 cm per 1 ms at 20°C.
Measured Timediff 5,584 ms

34,346 * (5,854/2) = 100,530 cm

See attachment (measured 2,123 ms which is 36,458 cm)

I would be happy if there is a way to display the distance directly in PicoScope!

Regards,
Wolfgang
Attachments
UltraSonic

Martyn
Posts: 3464
Joined: Fri Jun 10, 2011 8:15 am
Location: St. Neots

### Re: Math channels

I am not sure it would be possible to take this measurement, however if you can post a psdata file for the waveform you have shown in the image then we can take a look.
Martyn
Technical Support Manager

wgoettler
Newbie
Posts: 0
Joined: Mon Nov 24, 2014 10:28 am

### Re: Math channels

Hi,
maybe this one helps...
On "scope view 4" I'm using already the "Rise Time Measurement" which is in general not too bad.
Display the masurement result now on a scope view could be the solution.
Multiple echos could be a problem with this measurement, because only the first echo is relevant for measuring distance. Looking forward for your ideas...
Wolfgang
Attachments
20141126-0002.psdata
Ultrasonic Echo

Martyn
Posts: 3464
Joined: Fri Jun 10, 2011 8:15 am
Location: St. Neots

### Re: Math channels

You can get a similar result by using a maths channel, (3*A - B) in this example and then using High Pulse Width measurement (Cycle at Ruler 1) and just drag the ruler across the screen to near the ones you wish to measure.

The time between edges on two channels is already on our feature request list, although there are no indications as to if, or when, this will be implemented.
Martyn
Technical Support Manager

wgoettler
Newbie
Posts: 0
Joined: Mon Nov 24, 2014 10:28 am

### Re: Math channels

Not sure if I understood / did it correctly...
But "High Pulse Width" is not displaying a value.
Time measurement between edges in math channels would be great
Attachments
20141210-0001.psdata
US pulse width

Martyn