R
Rodge
- Jan 1, 1970
- 0
Hi,
I have a broken Webasto heater and i would like to understand a bit
more about their measuring circuit.
To ignite the heater they use a combined glowplug/flame sensor which is
connected to 12v DC. After x seconds the fuel injects and the heater
starts burning. The voltage to the glow plug is cut and the glow plug
acts now as a flame sensor by measuring the temperature.
If you measure the plug at 20°C it give abt 0.6 ohm. The working value
is between 0.6 and 2 ohm.
Now during the heating of the plug, the unit even measures his
resistance and my question is how they can do this? Put AC through and
make a devider with a capaciter which has the same impedance as the
plug at the AC freqency and measure the voltage over the capaciter?
Put a square DC to the plug and measure resistance every time the
voltage is 0, or are their better ways of doing this?
Kind regards,
Rogier
I have a broken Webasto heater and i would like to understand a bit
more about their measuring circuit.
To ignite the heater they use a combined glowplug/flame sensor which is
connected to 12v DC. After x seconds the fuel injects and the heater
starts burning. The voltage to the glow plug is cut and the glow plug
acts now as a flame sensor by measuring the temperature.
If you measure the plug at 20°C it give abt 0.6 ohm. The working value
is between 0.6 and 2 ohm.
Now during the heating of the plug, the unit even measures his
resistance and my question is how they can do this? Put AC through and
make a devider with a capaciter which has the same impedance as the
plug at the AC freqency and measure the voltage over the capaciter?
Put a square DC to the plug and measure resistance every time the
voltage is 0, or are their better ways of doing this?
Kind regards,
Rogier