Oil temp to analog input

[Wolf_Tm]

Hi,
as I want to connect a VDO 0-120°C sensor, I searched infos on vems pages about the Round Analog Input, but with no success.
Which signal does the Analog Input pin need? 0 to 5 volt?
Thanks

[VEMS]

Hello Wolf_Tm,

Perhaps you missed: http://vems.hu/vt/help/round/round_analog_input_settings.html ?

Round analog input accepts a 0-5v input signal, correct. It can created using either a temperature sensor with 0-5v signal output (hard to find) or when using a resistive type sensor (NTC or PTC) to connect a pullup resistor to 5v of value which matches the sensor resistance @ 20 deg C.

Then fill: http://vems.hu/vt/help/round/round_analog_input_curve.html to translate and scale ADC raw values to real world units.

Best regards, Dave

[Wolf_Tm]

Hi Dave,
I read that page but I'm an engine builder with zero electrician knowledge, so seems Extraterrestrial to me.
My NTC VDO sensor data are:
300 Ohm pull up
7.5K Ohm @ 0°C
2.2K Ohm @ 25°C
165 Ohm @ 100°C

How to connect the 2 sensor's terminals to the Round?

Thanks

[Wolf_Tm]

Hello Wolf_Tm,

Perhaps you missed: http://vems.hu/vt/help/round/round_analog_input_settings.html ?

Round analog input accepts a 0-5v input signal, correct. It can created using either a temperature sensor with 0-5v signal output (hard to find) or when using a resistive type sensor (NTC or PTC) to connect a pullup resistor to 5v of value which matches the sensor resistance @ 20 deg C.

Then fill: http://vems.hu/vt/help/round/round_analog_input_curve.html to translate and scale ADC raw values to real world units.

Best regards, Dave

Hi Dave,
can I use WBO2 pin5 to get the 4V source for the analog input?
Thanks

[gunni]

There is a 5v pin on the 36pin connector. purely for this purpose,
Pin 28.

[Wolf_Tm]

There is a 5v pin on the 36pin connector. purely for this purpose,
Pin 28.

Hi gunni,
unfortunately customer doesn't have a Vems ecu.
Anyway I have another 5v source on his ecu... so I assume I can use a 5v even if the analog input documents talk about a 4v?
Thanks

[gunni]

That 4v must be a typo, 5v is accurate. I missed that it´s a round.
4v is like the most difficult voltage rating to get without extra circuitry.

[Wolf_Tm]

That 4v must be a typo, 5v is accurate. I missed that it´s a round.
4v is like the most difficult voltage rating to get without extra circuitry.

Hi gunni,
thanks for the help:
could you please have a look here?

http://vems.hu/vt/help/round/round_analog_input_settings.html

[gunni]

What do you want me to look at?

The best way to make sure everything is reading right is to wire the sensor with pullup to the analog input and then adjust the scaling or curve based on empirical measurements.

[Wolf_Tm]

What do you want me to look at?

The pics in the link, where they talk about the 4v...

The best way to make sure everything is reading right is to wire the sensor with pullup to the analog input and then adjust the scaling or curve based on empirical measurements.

Yes, I unfortunately think you're right...
Thanks

[VEMS]

Hello Wolf_Tm,

The top of the help page states: "0-5V analog signal can be connected to the analog input (DSub15/pin8)". As stated before connect the VDO sensor (NTC or PTC) with a pullup resistor to 5v of value which matches the sensor resistance @ 20 deg C; like this 5v --- pullup resistor --- analog1 --- VDO sensor --- GND (connecting round analog input on junction of VDO and pullup resistor).

Middle of the page shows some additional info about changes to the analog input circuit in relation to round serial number, analog input 1 is shared with the button of the round.

I hope this elaboration clears things up for you.

Best regards, Dave

[Wolf_Tm]

Hello Wolf_Tm,

The top of the help page states: "0-5V analog signal can be connected to the analog input (DSub15/pin8)". As stated before connect the VDO sensor (NTC or PTC) with a pullup resistor to 5v of value which matches the sensor resistance @ 20 deg C; like this 5v --- pullup resistor --- analog1 --- VDO sensor --- GND (connecting round analog input on junction of VDO and pullup resistor).

Middle of the page shows some additional info about changes to the analog input circuit in relation to round serial number, analog input 1 is shared with the button of the round.

I hope this elaboration clears things up for you.

Best regards, Dave

Yes Dave,
it clears a lot a Documentation that IMHO is confusing.
I mean... if in that page it would have been written to connect the 20°C pullup resistor to a 5v source AND to the analog input pin AND to one sensor pin (with other sensor pin to ground), I would have had no problem to understand it.

But in that page, with no explanation they were just "some additional info about changes to the circuit", you can only find this schematic for "ANALOG INPUT - serial <2900 "



where you find
- a 1K resistor to 4V (and not 5V)
- a 1K resistor to the sensor ( and not the 20°C value resistor)
- a 2.2K resistor to Analog Input
- and a wire to an "A/D coverter input" !

Sorry if i got confused by that.
Thanks

[VEMS]

Hello Wolf_Tm,

I'll rewrite that help page a bit to make it more clear; Thanks for your feedback.

Best regards, Dave