Paschalis Posted October 30, 2020 Report Share Posted October 30, 2020 Hi all Can anyone who succesfully used a vems converter/divider help me with the wiring because I cant get any reading? Quote Link to comment Share on other sites More sharing options...
Adamw Posted October 31, 2020 Report Share Posted October 31, 2020 Assuming you have a VR wheel speed sensor, then its two wires connect to the "VR and Gnd" pads on the back end of the PCB. In the connector end, you need to connect pin 1 to ecu 5V, Pin 5 to ground, Pin 9 to the ECU digital input. Quote Link to comment Share on other sites More sharing options...
Paschalis Posted October 31, 2020 Author Report Share Posted October 31, 2020 4 hours ago, Adamw said: Assuming you have a VR wheel speed sensor, then its two wires connect to the "VR and Gnd" pads on the back end of the PCB. In the connector end, you need to connect pin 1 to ecu 5V, Pin 5 to ground, Pin 9 to the ECU digital input. Tried that already, no success..I get erratic misreadings without moving the wheel at all. Both Gnd tied together (correct?) first try was sensor ground of the ecu, second was a chassis ground bolt, same result. Also pin3 (reset pin) is supposed to be grounded too?? Lastly I have 2 wires coming from the sensor passing by the drivers seat, connecting the one doesnt give any readings ( having the car on a jack moving the wheel by hand), connecting the other one gives the strange readings even by not moving the wheel at all trying from 50 to 2000 as a filter on the DI options, same results, just a hint it s like it s climbing and falling like the idle moving, if I listen to the little flunctuation of the idle, this is how it moves, up and down reading from 100kph to 20 by having the car stillUsing the rear lhd on the attached diagram. It s a toyota corolla 99 model, so supposed to be a vr sensor. Do I have something wrong? Quote Link to comment Share on other sites More sharing options...
Adamw Posted October 31, 2020 Report Share Posted October 31, 2020 Pin 3 should not be connected. You will need to connect an oscilloscope to see what is wrong with the signal. Quote Link to comment Share on other sites More sharing options...
Paschalis Posted October 31, 2020 Author Report Share Posted October 31, 2020 4 hours ago, Adamw said: Pin 3 should not be connected. You will need to connect an oscilloscope to see what is wrong with the signal. Is it the signal or the noise? If it was something wrong, shouldn't be the abs checklight on from before? Quote Link to comment Share on other sites More sharing options...
Adamw Posted October 31, 2020 Report Share Posted October 31, 2020 It could be anything from the waveform upside down, a ground offset, the amplitude not meeting the minimum or a wiring issue. So the first step is to confirm you have a suitable waveform at the VEMs input pads, then the next step is to confirm you have an expected squarewave coming out the output side. Quote Link to comment Share on other sites More sharing options...
Paschalis Posted October 31, 2020 Author Report Share Posted October 31, 2020 Or I ll try as a first step another converter-only I found locally to see if it does a difference and then if it does at least for the 0 speed till 10kph (as much as the input frequency of link "permits" me) and if it does I ll go on with your design attached about dividing the frequency. I ll come back with my fidings tomorrow, thanks for the support, I ll be back tomorrow. Quote Link to comment Share on other sites More sharing options...
Paschalis Posted October 31, 2020 Author Report Share Posted October 31, 2020 30 minutes ago, Adamw said: It could be anything from the waveform upside down, a ground offset, the amplitude not meeting the minimum or a wiring issue. So the first step is to confirm you have a suitable waveform at the VEMs input pads, then the next step is to confirm you have an expected squarewave coming out the output side. You mean something like this attached in the photo? P.s. please check my previous message, I didnt quote you:) Quote Link to comment Share on other sites More sharing options...
Adamw Posted November 1, 2020 Report Share Posted November 1, 2020 the 4024 divider will only work for a hall effect sensor. Your ABS is VR. The VEMs device has a VR conditioner to first convert the signal to square wave, then the 4024 to divide it down. Yes that scopemeter would do the job. Quote Link to comment Share on other sites More sharing options...
Paschalis Posted November 1, 2020 Author Report Share Posted November 1, 2020 8 minutes ago, Adamw said: the 4024 divider will only work for a hall effect sensor. Your ABS is VR. The VEMs device has a VR conditioner to first convert the signal to square wave, then the 4024 to divide it down. Yes that scopemeter would do the job. The module I ll try will do the vr to hall convertting only and after successful testing with the DI on the ecu (I know it will exceed the 500hz frequency of the ecu but at least I ll be able to test 0kph when still and up to 20kph maybe?) If everything goes well then I ll use your circuit using the output signal of the module I ll test so as to cut/divide the frequency down. Correct? Quote Link to comment Share on other sites More sharing options...
Adamw Posted November 1, 2020 Report Share Posted November 1, 2020 ok sure. Quote Link to comment Share on other sites More sharing options...
Paschalis Posted November 1, 2020 Author Report Share Posted November 1, 2020 12 hours ago, Adamw said: ok sure. The vems one is too much sensitive so maybe even reads noise or something with the car sitting still at idle and this one I ve tried today which uses the max9926 ic starts to read frequency at around 50kph... What more can I try, have you got any clue? Quote Link to comment Share on other sites More sharing options...
Adamw Posted November 1, 2020 Report Share Posted November 1, 2020 You can change the voltage thresholds on the VEM's one. It is set to adaptive by default from memory and generally work very well. I suspect you have some other problem as I believe they need to see at least 0.2V even on the most sensitive setting. There should be info in the instructions or the chipset datasheet. Quote Link to comment Share on other sites More sharing options...
Paschalis Posted November 1, 2020 Author Report Share Posted November 1, 2020 1 hour ago, Adamw said: You can change the voltage thresholds on the VEM's one. It is set to adaptive by default from memory and generally work very well. I suspect you have some other problem as I believe they need to see at least 0.2V even on the most sensitive setting. There should be info in the instructions or the chipset datasheet. GND next to the vr signal in on the male connector is common to the pin 5 on the other side and bith need to be grounded on ecu sensor ground, correct? Or is it the other wire of the abs vr sensor as needed both of the abs sensor wires in the max9926 circuit? Quote Link to comment Share on other sites More sharing options...
Adamw Posted November 2, 2020 Report Share Posted November 2, 2020 Both VR sensor wires need to be connected to the input end and the pin 5 needs to be connected to ecu sensor ground. Quote Link to comment Share on other sites More sharing options...
Paschalis Posted November 2, 2020 Author Report Share Posted November 2, 2020 1 hour ago, Adamw said: Both VR sensor wires need to be connected to the input end and the pin 5 needs to be connected to ecu sensor ground. So the GND and the VR signal in on the male connector side (first connector on the photo above) is the input for both wires of the sensor?!?!?!? Quote Link to comment Share on other sites More sharing options...
Adamw Posted November 2, 2020 Report Share Posted November 2, 2020 yes. Paschalis 1 Quote Link to comment Share on other sites More sharing options...
Paschalis Posted November 2, 2020 Author Report Share Posted November 2, 2020 So that was the reason for the noise...nowhere noted...anyways...tomorrow will test it this way and I ll get back...thanks for the continued support...hope to get to the bottom of it and get a speed signal after all! Thanks again! Quote Link to comment Share on other sites More sharing options...
Paschalis Posted November 3, 2020 Author Report Share Posted November 3, 2020 On 11/2/2020 at 10:26 PM, Adamw said: yes. Things are like this Following wiring diagram of the car, if I connect GND to VR- and VR signal in to VR+ then I ll get no signal no matter at what speed. Connecting the other way GND to VR+ etc around I m getting noise when just starting the car and I also get the ABS check light on immediately. So 1st way is the correct one. Also tried with the change of mode with the silderblob to make the arming threshold at >=150mv, still no signal. I ve used the 1:1 output just to be on the safe side picking up any signal. The other circuit I ve tested was a vr conditioner using max9926 ic a friend gave me ready to be soldered (found it myself over the web too) which seems to be maybe more sensitive working fine (ok climbing the frequency too fast but I ll use your 4024 circuit) BUT detecting signal little over 55kph. It s something like this https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.ebay.com/itm/Dual-VR-conditioner-V3-PCB-by-Josh-Stewart-Speeduino-ASSEMBLED-/282773596435&ved=2ahUKEwjqiqrZmufsAhXDAmMBHSt_D1EQFjANegQICRAB&usg=AOvVaw3t3nZOHUCYYDBjddCLIuPe What more can I try? It s like the vems is more pro including the division too but the other one with max9926 seems more sensitive but need even more somehow. Quote Link to comment Share on other sites More sharing options...
Paschalis Posted November 5, 2020 Author Report Share Posted November 5, 2020 On 11/2/2020 at 10:26 PM, Adamw said: yes. I ve measured with a multimeter in dc mv and in ac and both give measurements when turning the wheel by hand, so I must make the converter a little more sensitive, have you got any clue? Quote Link to comment Share on other sites More sharing options...
Paschalis Posted November 9, 2020 Author Report Share Posted November 9, 2020 On 11/2/2020 at 10:26 PM, Adamw said: yes. It s all a matter of the vems converter. Even with a new abs sensor which is working fine with the other circuit I ve got with the max9926 ic, it's not working with the vems one. As soon as I "squeeze" the vems in my hands it's working fine for a few mins after I leave it again, I even used its 9 pin with a calibration on the digital at 380 and everything is fine but just for a few mins then I need to "press" again so it comes back again. I tried to "wire" directly the ecu cables (5v, gnd and DI) to the back of the female connector pins in case there was something wrong with the pins, still same thing, need to "squeeze" the pcb in my hand, something is faulty with the pcb, I ve sent an email to vems in HU and US, I hope they ll come back to me, although nobody responded to my previous mails asking for tech support...we ll see! Quote Link to comment Share on other sites More sharing options...
Paschalis Posted November 13, 2020 Author Report Share Posted November 13, 2020 On 11/1/2020 at 11:17 PM, Adamw said: You can change the voltage thresholds on the VEM's one. It is set to adaptive by default from memory and generally work very well. I suspect you have some other problem as I believe they need to see at least 0.2V even on the most sensitive setting. There should be info in the instructions or the chipset datasheet. Hi again Just ordered and received a new vems one to rule out any possibility (although in the end I damaged the original one, anyways) and it's working whenever it likes! If it works, it shows the speed just fine with /8 division and a filter of 390, I ve already soldered-blobbed the lower threshold mode 1 (>=150mv) although this iwas not a problem when working. They ve also sent me three tripletes of 470ohm, 4.7k and 2k7 to use somewhere for sensitivity but where should I use them? One more thing i ve tried and saw that it s not a matter of my sensor or abs system in general is the other circuit with the mac9926 ic, which is working just fine everywhere from 0 to 200kph, but it goes high frequency, almost touching 1200hz at 140kph. So I ve tried to use your 4024 circuit but as soon as I install the 4024, it doesnt show a sign no matter at what kph or which /x divide is used, although I admit I ve used a 18kohm resistor or which I had in hands and not 10kohm. Do you have something more to propose for the 4024? Quote Link to comment Share on other sites More sharing options...
Adamw Posted November 14, 2020 Report Share Posted November 14, 2020 As I said right at the beginning, you will need an oscilloscope to diagnose, otherwise you are just stabbing in the dark. You need to start at the sensor, see what the waveform looks like, see which side if any is connected to ground, then find where the signal is being lost or interpreted wrong by your circuit. I have used the VEMS device numerous times with no drama, it is a pretty basic device with good documentation so there is not much that can go wrong. It could be something like your ABS doesnt reference ground on either side of the sensor. Quote Link to comment Share on other sites More sharing options...
Paschalis Posted November 14, 2020 Author Report Share Posted November 14, 2020 9 hours ago, Adamw said: As I said right at the beginning, you will need an oscilloscope to diagnose, otherwise you are just stabbing in the dark. You need to start at the sensor, see what the waveform looks like, see which side if any is connected to ground, then find where the signal is being lost or interpreted wrong by your circuit. I have used the VEMS device numerous times with no drama, it is a pretty basic device with good documentation so there is not much that can go wrong. It could be something like your ABS doesnt reference ground on either side of the sensor. How can I easily check if grounded with a multimeter? And if indeed isn't grounded then this means that vems won't ever work? If this was the case, would the max9926 work as it does? If link ecu would be happy with high freq now I would be ready:) Tomorrow I ll have a scope and a multimeter to check what is going on...what do I need to measure? Quote Link to comment Share on other sites More sharing options...
Paschalis Posted November 15, 2020 Author Report Share Posted November 15, 2020 On 11/14/2020 at 6:11 AM, Adamw said: As I said right at the beginning, you will need an oscilloscope to diagnose, otherwise you are just stabbing in the dark. You need to start at the sensor, see what the waveform looks like, see which side if any is connected to ground, then find where the signal is being lost or interpreted wrong by your circuit. I have used the VEMS device numerous times with no drama, it is a pretty basic device with good documentation so there is not much that can go wrong. It could be something like your ABS doesnt reference ground on either side of the sensor. Finally it was the pin3 (reset) that after all needed to be connected to GND too, maybe this is a change in the last version of theirs!! I dont know but seems to be working flawlessly now! Quote Link to comment Share on other sites More sharing options...
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