Signal Generator Question - Page 1
Forum section: electronics / beginners

author: Ozzyla
author_rank: Newbie
timestamp: July 13, 2014, 11:44:17 am
content: Hi thereMy Name is Steven and im after some advice / helpIm a n00b Here and to electronics.I have been a motor mechanic for 30+ years. The majority of this time I have been involvedin engine tuning and EFI installations. A lot has changed in this time as far as carelectronics go's. I have also been involved in computers since the early 80s and usedto run a BBS for about 10 years till the internet started.For the past 10 years I have been self employed and do some IT work but mainly EFI installs and full car looms.I don't do a lot of tuning now days due to not wanting to breath fumes anymore.The jobs I do now involve full wiring looms for Motec or Autronic EFI, Motec Dash's,Motec CDI units and Motec PDMs (Power Distribution Modules)I have a couple of scopes, 1: a 2 channel automotive diagnostic scope for testing components.I also used it for testing REF and SYNC signals that are used to allow EFI ECUs to knowthe engine speed and cylinder position so it can deliver spark and fuel at the right times.The LCD screen on that scope was not really good enough and struggled for other jobs too.After looking around and finding this site including Daves reviews on youtube I got a second scopeA Rigol DS-2102A. Even though its over kill it works great and love using it.Now My question:More often im finding that I need to test things, just the other day I needed to test an ignitionsystem. I could check outputs to it but could not generate a test signal without making up atest rig using another ECU I had there. What I would have liked to do was use a signal generatorto generate the appropriate signal and check to see if everything was working (prove the ECU driving it was crap)Things that I could use it for, Testing HEI ignition, CDI Ignition, stepper motors for idle and cam control,electronic speedos and tachos, generating REF and SYNC signals for HAL or MAG sensors and sending them toECUs to confirm teeth spacing and numbers.From what I have found is im after a Generator that can make arbitrary waveforms.I saw a DG-4062 on youtube that looks to have a host of pre-generated waveforms to choose fromincluding a menu for Engine waveforms.Dose anyone know if these would do for what im after? or if the cheaper DG-1032Z would do the job?Also do any of these generators have the ability to copy waveforms from say a going ECU? If I have a going ECUand I want to make an exact copy of the ignition output for testing out of the car. I can get a good look at it with thescope, be great if the Generator could read and store it for later generating.If any of this is stupid then sorry, but any help or advice would be appreciated.ThanksOz

author: tautech
author_rank: Super Contributor
timestamp: July 13, 2014, 11:58:23 am
content: I can't speak for the Rigol DSO you have, but a feature of the Siglent DSO & AWG pairing is you can capture waveforms with their DSO's and transfer to the AWG with a USB stick for duplication.A little more research or a query to Rigol should give you the answers.

author: Unknown
author_rank: Unknown
timestamp: July 14, 2014, 06:31:05 am
content: Someone on the forum called "0xdeadbeef" posted about project he'd been working on called "NGen" which might be helpful. (see links below)Here is the post.https://www.eevblog.com/forum/oshw/ngen-a-low-cost-programmable-four-channel-engine-speed-simulator/The projecthttp://lemmini.de/NGen/NGen.htmlA short introduction to the project.http://lemmini.de/NGen/NGen%20Introduction.htmlI'm currently working on an ECU project which requires some crank / phase simulated signals to fool the ECU; mine are pretty simple and ECU specific but if you're looking at it from a diagnostic level it will certainly add a little more complexity to your requirements. I would probably create something with the functionality of NGen but with the capability of diagnostic scoping as well; that way you could simulate the signals to test the ECU and also diagnose faulty / out of range sensors / intermittent wiring glitches; I'm sure there's probably already stuff on the market to do that?

author: xwarp
author_rank: Frequent Contributor
timestamp: July 14, 2014, 02:48:01 pm
content: What ECU/ECM's are you guys working with?

author: Ozzyla
author_rank: Newbie
timestamp: July 15, 2014, 03:33:37 am
content: Quote from: xwarp on July 14, 2014, 02:48:01 pmThanks everyone for the reply's, surfed around, downloaded software and called Rigol, Have DG-1032Z Coming.I work with Motec M4, M4/8, M400 , M800, M8/4s ECUs. Motec Dashes, Motec PDMs, Autronic SMC, SM2, SM4.I avoid the others if possibleOz

author: rodpp
author_rank: Frequent Contributor
timestamp: July 15, 2014, 12:33:19 pm
content: I think you made a good choice.Look at the DG1032Z User Guide (http://www.rigol.com/download/Oversea/DG/User_guide/DG1000Z_UserGuide_EN.pdf) on page 2-81:Seamless Interconnection with OscilloscopeDG1000Z could interconnect with RIGOL oscilloscope which supports USB-TMC seamlessly and rebuilt and output the waveform data collected by the oscilloscope losslessly.

author: G0HZU
author_rank: Super Contributor
timestamp: July 15, 2014, 06:48:42 pm
content: I had a slightly more complex/complete requirement about 10 years ago. In my case I needed to emulate a complete vehicle (in terms of its EMS) such that the ECU would be spoofed into thinking it was in a real running vehicle.I ended up using a few cheapo MCU chips to do most of it. Back then a AWG wasn't really a viable option for me. Besides, a modern AWG seems a bit overkill for something like an ECU that only produces waveforms at a few kHz so I ended up replicating an AWG inside an MCU by writing the analogue waveforms in hex code within the MCU and I clocked each one out using a very crude homebrew DAC system.The whole jig could change engine speed and generate all the waveforms from the dizzy (the dizzy had more than one output and the outputs needed to be timed correctly wrt the teeth because each cog inside the dizzy was offset by a few degrees.It also produced the IGN confirmation signal (at the right time) and could generate the speed sensor waveform and it generated all the analogue sensor levels for the car. It could also generate a noisy (and user controllable) 'knock' waveform at the correct crank angle/window to spoof the ECU into detecting a 'genuine' knock event rather than just noise pickup in the sensor.So I could effectively spoof/drive the ECU as if it was in a real car. I don't think I could (as easily) do the above with AWGs even today. It took a few days to make it but it probably only cost about £25 in parts. I did keep meaning to make a more powerful (and neat!) version but this one did pretty much everything I needed.I also found the ECU manufacturer had hidden a high speed debug/datalog port inside the program code and I exploited this in the interface system as well. It allowed me to ask for status of all the variables in the ECU memory at about 200 requests a second. This made it quite easy to debug and reverse engineer the ECU program code. eg it was possible to do things like reverse engineer the knock sensing code and see how it stored the knock status in memory depending on engine speed and past knock history. it could all be displayed in real time on a laptop