DVM recommendation? (LAC)

Perry, Christoper (EDS) chris.perry at weyerhaeuser.com
Fri Jan 17 11:46:13 EST 2003

As a side note, you can use a regular DVM set to DC volts to check duty
cycle if you know the maximum ON voltage.  Duty cycle simply means ON or OFF
some percentage of total time.  Think of it as a simple switch.  Over a time
period of 10 seconds, if the switch is on for the full 10 seconds then the
duty cycle is 100 percent.  If the switch is on for 5 seconds then off for 5
seconds that is 50 percent.  On for 2 off for 8 equals 20 etc., etc.

Now for the ISV, for example, this ON/OFF thing happens many times a second,
but it is the same concept.  So, if you are working with 12VDC and the spec
is a duty cycle of 40 to 50 percent you could hook your DVM up and look for
40 to 50 percent of 12VDC or 4.8VDC to 6VDC.  80 percent duty cycle would be
9.6VDC etc..

Now of course you do need to know what the operating voltage is or this
won't work, but most stuff under the hood operates at 12V (or whatever your
alternator puts out).

Just something to think about if you are in a pinch.

Chris Perry

-----Original Message-----
From: R Mangas [mailto:porter_dog at hotmail.com]
Sent: Friday, January 17, 2003 9:47 AM
To: kentmclean at mindspring.com; quattro at audifans.com
Subject: Re: DVM recommendation? (LAC)


  One of the fuel injection control checks involves the duty cycle; can't
remember which one, but it's a rare-ish meter that will do it.


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