Fuel and Oil Pressure Transducers

[Sprocket]

I can get hold of pressure transducers from work, They are three wire five volt jobbies, there are four pressure ranges available. Very compact. I'll get a picture up soon. They are used on Water chillers for the refrigeration circuit, and have also been used on the water side.

Anyway, If I remember correctly, there are some Analogue input channels on board internaly.

What I would like is information on seting up of these, If any one can help.

I actualy intend to use these pressure channels not for the fuel/ oil, but for Rad and coolant jacket pressures. Long story

These will be monitoring channels for data logging only.

If I cant get this to work ( really daft if I cant ) I will have to use one of our PLC's to log the transducers, its just a pain in the arse to rig up a 24v system to run it from

Thank you in advance

Have a Happy new year

[rob@vems.co.uk]

With the Webshop VEMS units the pins EC18-pin6, 12 & 16 are spare analog inputs, these connect up to the MCP3208 A2D converter - the schematics should show you on your board which channels go to the break-out holes on the main PCB.

[Sprocket]

I have been looking at the schematic and the board lay out and my head is bashed, lol. While looking at this, I think I may have found the reason why EGT2 reads about 200 degrees out . I wired it as per the build procedure, lol, its not according to the schematic. The build procedures are screwd up. I think the schematic is screwed up as well:D There is no contiuity with anything LMFAO

Firstly I need to work out how im going to get round the connectivity, as im running out of useble pins . I have a 'cunning plan' to get round that, but for now, can anyone confirm the following ADC channels and which are free for what type of input. Please be gentle, im only a novice where electronics is concerned


ch0 opamp U13D JP14-1/2 (pressure transducer? why +ve and -ve?) Unassigned?

ch1 opamp U13A JP9-1/2 (pressure transducer? why +ve and -ve?) Unassigned?

ch2 JP16-4 or opamp U17B (digital or 0-5v?) Unasigned?

ch3 EGT2 (assigned)

ch4 EGT1 (assigned)

ch5 opamp U13B or JP19-1. EC18-16, (assigned digital in) for ALS/ Shift cut with pull up resistor.

ch6 JP11-1 (not assigned). EC18-6, but EC pin used for DPAK FEF, onboard wiring removed. (thermistor, digital or 0-5v input?) see schematic, pull up resistors installed, why?)

ch7 JP11-2 (not assigned). EC18-12, but EC pin used for DPAK FET, onboard wiring removed. (thermistor, digital or 0-5v input?) see schematic, pull up resistors installed, why?)



Secondary VR is not as of yet connected to any EC pin, on another note, the shcematic says to remove resistor R59 when proprietary Audi triger installed. Where is this? cannot find it anywhere. Is this something I still need to do? what about R58?

Also on schematic it shows analog in channels 7 and 8 (is the schematic screwed up? should this not be channels 6 and 7?) to have a 5 volt pull up intsalled for thermistors, is this correct? I have not physicaly checked the board yet to see if they are indeed installed.

I will also post this on the wiki, but its taken me 3 hours to work this lot out and post so it can wait till tomorrow, now, lol check the post time . But if anyone can shed some light

[Sprocket]

More research shows that Exhaust Back Pressure (EBP) and Fuel pressure (FP) inputs were originaly designated to pins EC18-2 and EC18-3 respectively. The harware is onboard and is usualy ignored with those EC18 pins being used for the Knock.

Looking at the schematic, it shows a 5v pull up and filtering outputing to JP18 and JP17 respectively. Shcematic notes these as 'To AD' so presumebly its an onboard wiring to spare ADC input channels.

The actual pressure sensing devices as far as I can work out are simple pressure sensors requiring the pull up resistors preiously noted above, much like a thermistor. I intend to use a transducer, where there is a 5v+, ground and signal, acting in much the same way as the TPS for instance.

I again assume I could still use the intended protection and filtering circuit, but remove the pull up resistors, then link to the ADC.

Big question is how I link this up to the firmware. I again assume that I would need to create ebpfactor.inc and fpfactor.inc files, compile firmware and upload??.................



Going back to my last post, ADC channels 6 and 7 show a pull up resistor on the schematic, these are not installed. I did however install a 2k7 resistor to channel 7, and i shall use this as a digital in, rather than using an external pull up resistor on channel 5. Channel 5 and 6 are now analogues.

Connectivity has been overcome, and I now have the ability to use the three ADC inputs, The two Pressure inputs, the two WBO2 inputs, the two DPAK FET outputs, the stepper output, the Secondary VR input and the one wire interface, that I still need to fathom out lol. Also managed to squeeze the 9 pins for the lcd and the 3 for serial coms in there as well. All that without too much problem. Ill get some pictures up later

Just need some help connecting the transducer to the input the input to the ADC and then the ADC to the firmware

Just one other thing, whoever thought of the Genboard needs a gentle pat on the back, there is SO much on there, it is quite surprising Some thought needs to go into how to get to it though maybe im not the first one to do this, but i dont think its too hard to adopt on the next generation boards piccies later

[Sprocket]

I found a data sheet for almost identical pressure transducers. It says the seal material is neoprene with a max temp of 50c. I doubt very much that if this seal was on the medium side of the diaphragm, it is not the ones we use at work, as the refrigerants would destroy them. Bit unsure what the 'seal' is refering to.

Any way, here they are, http://www.parker.com/euro_lucifer/datasheet/Datasheet_6603_ERXC_100_PT.pdf

These are labled as a Suction transducer(refrigeration), this has a minimum kpa reading of -46 kpa and a maximum kpa reading of 954 kpa giving a total 1000 kpa range. We have other pressure ranges, though the higher ones would be useles to our needs as they do not read below 246 kpa and in excess of 3000kpa. As far as I am aware there are four pressure ranges, low (rare), medium low (very common), medium (common), high (very common).

[Sprocket]

I cut open two of these transducers today to see how they are constructed and to get a better understanding of how they operate. Very interesting



There is a ceramic load cell, then there is a signal conditioning circuit with an over voltage and reverse polarity protection circuit. There is an o ring that seals the load cell to the body, unlike I said earlier, I was assuming things and you know what happens when yyou assume things. Still the Neoprene seal is not compatable with R134a, lol.

I know vibration is not an issue with these, but the temperature may be, however, that said, we use these units didectly on the top of the compressor discharge heads and that temperature is anywhere from 40 to 60 degrees. I think they would survive quite a reasonable time. The other thing I wasnt sure of was the use of these on fuel. I dont think it will be a problem, Neoprene is reasonably well resistant to fuels and oils and these units (low pressure) have a very good seal, up to 16 bar.

The output is 0-5v linear, so i would suggest that any free ADC input is useble, and the megatune gauge scaling in Vems.ini just needs configuring.

still be interested to know what the ADC 0 and 1 channels are dedicated for?

Watch this space

[GintsK]

Today I found this webpage:
http://rush.smolly.nl/changes/change4_2.htm
Super 7 Rush: Engine Swap

Fuel Pressure Sensor (0-10 bar)
(VW/Audi 06E 906 051E)
 

1. GND
2. signal
3. +5V supply

Pressure [bar] = (2.47 * U [V]) - 1.12
 

[Sprocket]

I'll be honest and say that they look pretty much similar

[magoo]

Today I found this webpage:
http://rush.smolly.nl/changes/change4_2.htm
Super 7 Rush: Engine Swap

Fuel Pressure Sensor (0-10 bar)
(VW/Audi 06E 906 051E)
 

1. GND
2. signal
3. +5V supply

Pressure [bar] = (2.47 * U [V]) - 1.12
 

Hi,
sorry for lifting an old thread.
I'm just curious if some one has used this sensor?! I got a couple of them and my thought was to use them for logging oil and fuel pressure.
Is it ok for use with VEMS?

[gunni]

Sure