Do you use PC_GIM (General Input Unit)?

It is for calibrating the sensor not the GIU. If you have a temperature sensor that is reading say 22.5 degrees and you have something to calibrate it against, ie highly accurate meter, which says 21.5 degrees, you could then adjust up/down the reading of the GIU to match the more accurate reading. This is a standard practice in other systems I've worked with and is easily achieved through software. Something to think about. Regards, CC&C.

 

CC&C,
I can see where you are coming from, and it shouldn't be too difficult to do in the s/w, but can't you do that already with the existing features (might not be as obvious). The offset (when it's fixed) could be used, or even the library, although this is probably not as easy. Can either of these methods be of use to you?

Regards, RatDeSewer

 

RatDeSewer,
I hadn't thought of using the offset for that purpose, good idea. It would obviously give a slightly different result: y=(mx+b+Cal Factor) versus y=(m(x+Cal Factor)+b). As long as anybody else who came later understood what you were trying to achieve, I can't see why you couldn't use it. Having it in a separate field means it might be more easily understood though.

I've asked before (Nov 2004) about displaying values from the GIU and the answer I got was that I could in C-Touch but only as a 0-100% level and "The General Input Unit can also broadcast measurements on the Measurement Application. There are currently no devices which support the Measurement Application, but there will be soon." Is there an update for what devices?

Thanks, CC&C.

 

Still no Negative Offset

>>>> I know there wouldn't be many sensors that
>>>> would need this, however, can make the
>>>> offset accept negative numbers. (i.e. A
>>>> 0-1VDC temperature sensor might be
>>>> scaled -10C to +50C.)

>> The firmware should already be able to
>> cope with this (uses floats here), so it
>> appears to be a software issue again -
>> more for Daniel.

I'm running the latest Toolkit. I have three sensors - Light, Humidity and Temperature. The ranges and consequently the multipliers and offsets need to be as follows.

Light
0 to 5000 Lux, multiplier 19.6078, offset 0 ---- works just fine

Humidity
0 to 100%, multiplier 0.39216, offset 0 ---- works just fine

Temperature
-50 to +70 degrees, multiplier 0.27451, offset -13.7255 ---- ooops

I don't think I can have either a negative or non-integer offset - let alone both! Ideas (or something in the next Toolkit release) very welcome.

Nick

 

Great response !

>>> Thanks Nick, I've logged that (#9226)

Daniel, many thanks for the prompt and positive response.

Thanks also for not pointing out my rubbish maths! It should of course have said:

Temperature
-50 to +70 degrees, multiplier 0.47059, offset -50 ---- ooops

So, for my particular case, the need is only for a negative offset - integer only would do the trick.

Thanks