Sort of to do with EFI (more electronics)

[Jeffrey Engel]

Op-amps.  You can scale and invert, even deal with shifted grounds 
and stuff like that.  The nice thing is they're cheap and blow up 
before the ADC if something nasty comes in on the line you're 
measuring.

======================================
> Date:          Thu, 23 Oct 1997 17:14:52 +1000
> From:          bohblesku <bohblesku at gatekeeper.viper.net.au>
> To:            diy_efi at coulomb.eng.ohio-state.edu
> Subject:       Sort of to do with EFI (more electronics)
> Reply-to:      diy_efi at coulomb.eng.ohio-state.edu

> Hi,
> The following email is about A-D conversion of inputs from various
> sensors. It's not really about EFI (sorry) but as some of
> you may know the answer, I post it here :o)
> 
> I am in the process of making a digital data-logger which uses an 8051
> (similar) with 6 channel A-D conversion on chip. All seems to be ok. I
> have the LCD, a PIC 16C55 controller board interfacing to RS232 that all
> works ok. Now, the quest is to interface it to the real world. In
> researching this, I have decided to use 80C550 or 87C748. There is no
> reqirement in the design to use a serial link, so they should be ok.
> The questions I have are;
>     The oil temperature, water temperature, oil pressure sensors use
> what range of voltage? It is my understanding that they ground a "12V"
> signal and the resulting current flow is used as the measure of sensor
> range. Is this true for all the sensors?
> If you know about A-D conversion, I am stuck at this point not being
> able to interface the 8051 family A-D converter to the real world. ( I
> am a computer engineer, I know a little about digital electronics, but
> obviously lack quite a bit in this area )
>     I found a great site www.8052.com that gives many details about the
> chip, interfacing and programming. At the moment, everything to do with
> the 8051 seems to be sorted out except for the Analogue part!
> 
> I would appreciate any help or suggestions, if you are interested in the
> project, it is no top secret, so I would be pleased to share more
> details with you.
> 
> Thanks in advance
> Tim Freeburn
> 
> 
> 
> 
> 
je
jengel at fastlane.net

     "I can resist anything but temptation"
                                  Mark Twain