Author Topic: VR to hall converter unusable!  (Read 122 times)

Offline pamarakos

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VR to hall converter unusable!
« on: October 31, 2020, 11:19:44 am »
Hi all
Just received the LM1815.4024 so as to use my stock toyota corolla 99 model abs sensor as wheel speed sensor for my link ecu Digital Input.
After wiring it all assuming correctly leaving everything at default and "stealing" signal from the abs sensor from one wire of the two passing by the drivers seat from the rear LHD sensor (since the other wire gave no readings) I have erratic readings with the car standing still from 120kph to 20kph. Messing around with the filters on the ecu menu for the digital input gave no better results.
So couple of questions to check my wiring at first
On the pcb: 1) Wired the pcb vr signal input (without soldering just for testing) to the abs sensor wire (tried both, only one gave readings but the unstable ones, either miving or not moving the wheel having the car on a jack) 2) Ground was wired together with the dsub9 male connector ground either to the ecu sensor ground or tried also to a chassis ground on a bolt (same readings on both)

On the dsub9 male connector: 1)pin 1 5v from the ecu 2) Reset pin is underlined on the instr.page to be grounded or for expert users to have it 0 or 5v, anyways, I just grounded it by bridging it to pin5 (but also tested it without having it grounded)
3) pin5, together with the pcb gnd, grounded to sensor ground from ecu
4) used the /4 output but I guess didnt matter at all since I wasnt able to get stable readings even by having the car still.
From readings I ve found in here mode 1 (which is the default one)is the correct one for stock abs sensors, so didnt mess it with it at all, what more can I try? Have I done something wrong?
Thanks for your time

Offline pamarakos

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Re: VR to hall converter unusable!
« Reply #1 on: November 14, 2020, 05:38:55 am »
It's the second vr2hall converter that I'm receiving and cannot get it to work, I own a Toyota corolla 99 model equipped with ABS of course, so ordered this to make use of the sensors as wheels speed source to feed my link ecu digital input.

Things are like this: I've wired the +5v, GND and signal out to ecu using the /8 from the one side and vr+ and vr- from the other side. Have I done something wrong? Do I need to connect the Reset counter pin to GND?

Results are when and if the converter is working, it's working just fine, with the /8 I needed a little adjustment in the link ecu settings and voila my speed was there. After my first 2-3km driving around, it stopped. So you say I guess wiring issue..but same time once it's working and next moment it's not. Even tried a 2nd sensor, same results, even ordered a 2nd adapter again same results. On the 2nd order received there were 3 triplets of resistors, 470, 2k7 and 4.7 if I remember correctly,so where shall I test/install these?

Two hints: One is if while driving around and no sign of the converter working I touch it with my hands and pushing it, it starts showing speed just fine, this was happening with both the converters.

Second is if I let it "rest" for a while, then the first time spinning the wheel even by hand having the car on a jack, is always successful, BUT not the second one.

Again PLEASE don't start asking me about the wiring, I've tested it with a MAX9926 circuit and working just fine every time, using it two days in a row not a single problem anywhere. I need the VEMS one and ordered it for it's divby steps because my ecu can handle up to 500hz signal and MAX circuit which doesn't offer divby options has already 1000hz at 70kph. If someone can point me how to use only the 4024 part of the VEMS, it's fine for me although the MAX one is a bulk pcb, so I keep on struggling to make the vems one working ok, having it in its connectors-casings!

Ive also tried to set it to the most sensitive mode with the solderblob on the first two points with the >=150mv threshold, no luck too. I can't figure out what more to try, can you please help to get to the bottom of it as it drives me crazy? How is it possible to "squeeze" something by hand and have it working great like this until you leave it? Is ther something wrong with the ground?

One more hint (maybe) : If I add a 4024 ic after my max9926, I get no signal too no matter what /x I choose to use or at what speed I drive!

The 1:1 output on the vems one is directly from the lm1815 just to give it a try tomorrow?

What does anyine need to measure so as to help?

Thanks for your time