Calibrating a CO meter
12-18-2002, 06:32 PM
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Burning Brakes
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Calibrating a CO meter
Thought I'd throw this one out there - it's not really off-topic since I'm going to set the CO on my 944 if I can get this thing to work.
I bought an old (early '80s?) but professional automotive CO meter off eBay. It's made by the Peerless Instrument Company of Chicago, long since defunct it seems.
It's comprised of two pieces - a base unit that has a pipe that gets the actual exhaust gas from the car via a CO tube or the tailpipe, and a hand held meter that is connected to the base unit with about 15 feet of cable. The base unit takes a couple C cell batteries (the batteries in the unit are fresh).
All the controls and the meter (analog w/needle) are in the hand unit. The controls are simple - there's a 3 position switch and two trim pots. Position one is off. Position two is "calibrate" (my apoligies, the tool is at home and I'm at work), and position 3 is for doing the actual measurement. In position 2, you can fine tune the position of the needle by turning one of the pots. There's a clear marking on the meter where you should move the needle to when you calibrate it. Then in the 3rd or "on" position, the needle sort of floats around like it's actually measuring something. The other pot can adjust the needle when in position 3.
If you take the back cover off the hand unit, there's a third calibration pot which clearly isn't meant to be twiddled by the user (I haven't but who knows who else might have).
So if there is anyone out there who has info about these things or knows how to set them up or calibrate them, or knows who can, that would be awesome.
I'll try to post some pics tonight.
Bryan
"At Porsche, we only make sports cars"
I bought an old (early '80s?) but professional automotive CO meter off eBay. It's made by the Peerless Instrument Company of Chicago, long since defunct it seems.
It's comprised of two pieces - a base unit that has a pipe that gets the actual exhaust gas from the car via a CO tube or the tailpipe, and a hand held meter that is connected to the base unit with about 15 feet of cable. The base unit takes a couple C cell batteries (the batteries in the unit are fresh).
All the controls and the meter (analog w/needle) are in the hand unit. The controls are simple - there's a 3 position switch and two trim pots. Position one is off. Position two is "calibrate" (my apoligies, the tool is at home and I'm at work), and position 3 is for doing the actual measurement. In position 2, you can fine tune the position of the needle by turning one of the pots. There's a clear marking on the meter where you should move the needle to when you calibrate it. Then in the 3rd or "on" position, the needle sort of floats around like it's actually measuring something. The other pot can adjust the needle when in position 3.
If you take the back cover off the hand unit, there's a third calibration pot which clearly isn't meant to be twiddled by the user (I haven't but who knows who else might have).
So if there is anyone out there who has info about these things or knows how to set them up or calibrate them, or knows who can, that would be awesome.
I'll try to post some pics tonight.
Bryan
"At Porsche, we only make sports cars"
