Simulating noisy, real world DC of a truck - Page 1
Forum section: electronics / testgear

author: David Balcaen
author_rank: Newbie
timestamp: July 06, 2015, 11:58:09 am
content: Hi,Looking for a way to simulate the real world of DC of a truck on my test bench. Spikes when starting, noise from Alternator, loose connections, contactors (relays) turning on and off, heavy loads cutting in and out. When I put my scope on the DC supply to telematics devices worked with there is all sorts of garbage on the DC line. Some small, mv, others large, several volts, but short time span (10-20msec) As best I can I wish to simulate this GARBAGE DC environment and see how our devices behave. Thinking a Programmable Power supply but I have never used one of these and do not know if it will manage noise up to, say, 10 kHz. as well as longer period voltage swings, spikes and relay noise simulations. Any ideas? Anyone already done this? No, I don't want to move my bench into a truck!PS - I think what I am looking for is an Arbitrary Waveform Power Supply, perhaps like a Hameg 8143 (discontinued) Of course, cost is always an issue and not sure I can go over $500.David

author: joeqsmith
author_rank: Super Contributor
timestamp: July 06, 2015, 12:16:07 pm
content: There are test standards for this. They used to provide the circuits used to simulate the transients. Seems like they would call out a specific air conditioner clutch for example as part of the transient generator. The standards should be controlled by SAE and ISO.

author: marshallh
author_rank: Unknown
timestamp: July 07, 2015, 03:25:09 am
content: You could probably get some huge chokes and caps and wire them up to relays and use some arduino to switch them on and off randomly. Run a 12V CCFL light off it for extra noise.

author: RobertHolcombe
author_rank: Frequent Contributor
timestamp: July 07, 2015, 07:26:16 am
content: I've been looking into this too, these are the standards which apply as joeqsmith mentioned. I haven't gone far with it, so would be interested to see any progress you makehttp://www.iso.org/iso/catalogue_detail.htm?csnumber=50925http://standards.sae.org/j1455_200606/http://standards.sae.org/j1113/1_201310/

author: Warhawk
author_rank: Frequent Contributor
timestamp: July 07, 2015, 07:52:30 am
content: Quote from: David Balcaen on July 06, 2015, 11:58:09 amHi, I was dealing with the same thing. I ended up with LTspice. Maybe this helps you:https://www.eevblog.com/forum/beginners/peak-detector-for-frequency-measurement-in-a-noisy-environment/msg677583/#msg677583https://www.eevblog.com/forum/projects/rigol-ds1000z-csv-to-ltspice-(pwl)-parser-(testers-welcomed-!)/msg673153/#msg673153What range of output power you need ? I can imagine that you put this CSV list (as far as memory allows) to arbitrary waveform generator and boost the signal by output amplifier (I've done that before).E.g. you can use some power opamp in analog adder configuration, first input for DC supply, second input for AWG.What do you think ?

author: AndyC_772
author_rank: Super Contributor
timestamp: July 07, 2015, 08:09:28 am
content: I've rented a pulse generator from an EMC test lab for this purpose.Another option might be an AWG plus an output amplifier, which need not be anything exotic, and could possibly just be an audio amplifier IC (if the output voltage range is OK).