DMM freq & O2 sensor cross counts?

[Lance Morgan]

Can a DMM/DVOM, w/frequency capability, measure how many times per
second 0.45V is being crossed?

 

[Bruce Chang]

Can a DMM/DVOM, w/frequency capability, measure how many times per
second 0.45V is being crossed?

No.

 

[Clint Sharp]

Can a DMM/DVOM, w/frequency capability, measure how many times per
second 0.45V is being crossed?

Probably not, a lambda sensor switches (usually) a couple of times a
second, you need a pulse counter.

 

[Lance Morgan]

In message <[email protected]>, Lance
Morgan

Probably not, a lambda sensor switches (usually) a couple of times a
second, you need a pulse counter.

It seems a minimum of 3-10 Hz is specified for Zr type sensors.

Does the freq feature only work if a OV baseline is involved?

As a possible alternative? to a bench o-scope, a DSO, a high-tech
hand-held scope, or an A/F meter, it would be interesting to see what
the O2 sensor(s) is reporting (Max/Min/Avg/Hz) while driving, when a
fuel related driveability problem is actually occurring (running DMM
test leads from sensor into cabin)

Thank you

 

[Harvey White]

It seems a minimum of 3-10 Hz is specified for Zr type sensors.

It seems that you'd like to have a data logger instead of a meter.
Time stamped data might be what you want. I'd suggest something from
either James Electronics or JDR... those are two places that I think
might have them... no guarantee that they are the best prices...

Harvey

 

[B. B0dnar]

Use a 'scope. On a hot O2S, the switching time ("rise time, fall time"
if you're into EE) on a high speed idling engine for a zirconium dioxide
oxygen sensor should be under 100 milliseconds. If the sensor's output
lead's close to the ignition system, you may notice hash on it (e.g., on
my 1995 Ciera with 3.1 liters engine, there's plenty of hash -- scan
tool intermittently shows cross-counts of 255 -- this occurs only when
O2S output voltage > 450 mV).

If switching time's greater than 100 mS, raise the engine rpm. If it's
still greater than 100 mS, replace the oxygen sensor.

Oscilloscope type doesn't matter. I originally used a 25 MHz dual
channel Heathkit analog scope; now it's a Tektronix THM465
"etch-a-sketch" DSO (both are obsolete). You don't need anything that's
high bandwidth (this isn't Schottky TTL or ECL circuitry you're
troubleshooting or designing).

Regards,

Bohdan Bodnar