additional analog sensor wiring

[RHD]

This may be seem like a silly question to those who know electronics well but, what are the correct wiring diagrams for using a 1 wire or 2 wire analog sensor with the analog inputs ( such as oil temp fuel pressure etc?) the manual explains some of the function but no clear wiring example.

I assume a 2 wire would use the 5v supply to the other pin? or would it still use the sensor ground?

But how about a single wire pressure sender??

thanks

[gregpe]

in both cases you need pull up resistor.. to 5 volts i think two wires need 0v sensor and signal signal in joint with 5v with pull up resistor.
google voltage divider you will find all you need.

[RHD]

Ok I think the user manual should have wiring diagrams for these this is a very common application, fuel/oil pressure/ temp etc.

can we not just connect a 2 wire sensor to the regulated +5v supply and the other to the Analog Input??

How about using an analog input for 0-5V external wide band AFR controller?? my tuner is waiting to do this now !!... where do we connect or ref ground? chassis or sensor Gnd?

thanks


p.s our pressure sensor has 3-160 ohm range

[gregpe]

Again look at Voltage divider how it working.. for me is a basics knowledge and understanding sensors you cant connect it as you write you need pull up resistor to signal and sensor ground to the other pin and also note that calibration curve is not linear in case of this sensors.

[RHD]

OK so how much load can i draw from the 5v output??

If I connect the sensor (3-160 ohm) to the Analog IP and sensor ground and pull up the An/IP with maybe 100 ohm resistor? from the +5v output, that will give me about 0.1v to 3V signal range. Is that correct?? That should be ok

If i install 3 of these (oil & fuel Press + oil temp) will that overload the 5v supply??

Otherwise I can connect it to the chassis ground and pull up the An/IP from the battery voltage with about 220ohm resistor and have a 0.1 to 5v signal. Is that correct? BUT! this will be less stable due to fluctuations in batt voltage and alternator etc or is this not worth considering??

[gregpe]

5 volt is regulated from ECU do not changing with battery voltage..

[Jadzwin]

For pressure senders I suggest to use piezoelectric (like MAP sensor) not a resistive ones.

[RHD]

ok how about temperature senders???

[Jadzwin]

They are resistive so you need to add pullup.

[RHD]

Ok thats what i figured but whats the lowest combined resistance i can use connected to the 5v supply?

is 100ohm ok?

If its too big the analog range gets very small. if its too small the 5v supply is loaded lots.

thanks

[Jadzwin]

It should be ok.