Input calculations

Submitted by robur on Fri, 02/10/2015 - 16:21

Hi,

I think this is possible but have failed so far to get it to work.... wondering if someone might be able to point me in the right direction?

I have 3 Inputs:

InputA, InputB, InputC and would like to calculate inputD from them like so:

InputD = InputC/(InputA-InputB)

Fingers crossed it can be done :-)

Cheers.

Re: Input calculations

Submitted by robur on Fri, 02/10/2015 - 18:50.

Hmmmm, I think I can see how this could work but need to be able to calculate a reciprocal of an INPUT value, wonder if this is possible?

Re: Input calculations

Submitted by pb66 on Fri, 02/10/2015 - 22:15.

A little context would go a long way and some indication of system set up emoncms version etc will help, but assuming you are referring to inputs to emoncms, I think most versions will probably do what (I think) you are after. although v9 may make the calculations easier.

To calculate "InputD" you could use the "-input" (or -feed if B is logged) process to subtract B from A and log that to a feed eg "InputAminusB", in the "InputC" proceslist you would then use "/ feed" with the "InputAminusB" feed to arrive at "InputD".

For the reciprocal you need to use the "reset to zero" process that gives you a clean slate at any time in the processlist. After that add a "+ 1 calibration" on which you can then use a "/ input".

Paul

Re: Input calculations

Submitted by robur on Thu, 08/10/2015 - 07:43.

Hi Paul,

Thanks for your reply and apologies for the flakey question - you're quite right :-) This was indeed an EmnCMS question re: V8. Now working with V9 which is looking very nice indeed and much easier to make the calculations.

Thanks again.

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