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Author Topic: SoR_Scope help  (Read 1025 times)

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Offline lakepir8Topic starter

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SoR_Scope help
« on: February 12, 2011, 09:37:07 AM »
I purchased the Axon controller specifically to use as a scope, and I want to look at 120v AC. Does it have to be modified?

What kind of probe do I need?

Offline hopslink

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Re: SoR_Scope help
« Reply #1 on: February 12, 2011, 05:53:51 PM »
The SoR scope page says "By default hardware you can only measure 0V to 5V signals."

120V(rms) AC signal is -170V to 170V, so yes you need to do need to modify it. If you don't know how already then you really shouldn't be working with these sorts of voltages. My advice is to get someone who knows what they are doing to supervise you directly. All the best, and stay safe!

 

Offline lakepir8Topic starter

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Re: SoR_Scope help
« Reply #2 on: February 13, 2011, 07:21:58 AM »
That's really not help. Is it even possible to use the Axon to measure 120V?

Offline waltr

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Re: SoR_Scope help
« Reply #3 on: February 13, 2011, 09:21:11 AM »
It is possible BUT you need a properly designed circuit to:
1- reduce and shift the voltage to levels acceptable to the Axon, 0 to 5V.
2- provide adequate isolation to prevent electrocution.

What measurement of the AC Mains do you what:
VAC RMS
V peak
V Peak to Peak

Do more googling for circuits. A circuit that works for any 5V micro-controller will work. It doesn't need to be just for an Axon.
Some that I found:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1255308778
http://www.microchip.com/forums/m138162-print.aspx
http://www.eevblog.com/forum/index.php?topic=106.0
http://bbs.circuitcellar.com/phpbb/viewtopic.php?f=11&t=3612

If you are just interested in look at the AC waveform then a 120 to 6.3V transformer and a resistor voltage divider is an inexpensive method that does provide isolation.

Offline Admin

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Re: SoR_Scope help
« Reply #4 on: February 13, 2011, 06:23:44 PM »
lakepir8, you can buy sensors that will connect to the Axon ADC to let you measure 120 VAC.

For example:
http://www.cy-sensors.com/VoltageSensor.htm
http://www.phidgets.com/products.php?category=8

Are you trying to measure voltage or current?

 


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