problems getting egt-k sensor to read in utcomp

[svein]

Hi!
I recently installed an egt-k sensor with amplifier and connected it to utcomp. No matter what I do, utcomp reads 0C and occasionally blink up with 1degree - but very seldom.

I have mounted the sensor itself in the exhaust manifold. The amplifier is located near my fuses on top of the battery, just a short meter from the sensor. I have the rest of the cable coiled near the battery. From the amplifier, it is about 4m of 1mm2 cable too utcomp.

I have played around with the ground connections: Grounding the 12v input only, 12v input and 5v output, and 12v input and egt-k sensor minus, but the reading stays steady at 0.

I´ve measured roughly 7mV on the 5v output, no matter if the car is running or the car is cold.

Any suggestions to what might be the next step in fault-finding it?

Thanks a lot,
Svein

[ArT]

Hi Svein, it seems to me that your amplifier does not have power supply connected. It should be +5V output (between OUT and GND) while TC+ and TC- are disconnected. Please check if you have the same connection as in datasheet (page2) https://www.reveltronics.com/downloads/ ... eet_en.pdf
Amplifier should have minimum +8V power supply (max 32V) so +12V from battery will be fine.

EGT-K connection wiring diagram

egt-k_connection.jpg (43.19 KiB) Viewed 137355 times

[svein]

Hi Art,
and thanks for the quick reply!
I have measured 14,6v in on the amplifier on the power supply input. I also measured some fluctuating mV values that were hard to determine if was anything at all on the input from the EGT-K probe.
I will try to disconnect it and measure the output without the probe connected tomorrow.

Cheers,
Svein

[ArT]

Hm please check it with disconnected thermocouple - only power supply connected. It should be +5V on output.

The second test is short circuit test on input - when you connect TC+ to TC- you should have amplifier temperature on output - it will be about 0,1V in room temperature (20C)

[svein]

Did some more testing today.
There is no difference in the output with the input short circuited or completely disconnected. Today, the readings was around 5-7mV - but I'm not that sure about the accuracy of the voltmeter I'm using so it might as well be nothing.

The output terminal feels very wobbly, so I'm wondering if I might have to open it and have a look inside if I could have managed to break of something during the initial install. Is that a bad idea - alternatively do you have any other suggestions?

Thanks again,
Svein

[ArT]

Hmm are you sure that you have power supply on power input terminal?
You can open it and take a look. Is it 1CH variant? We can check it also. Please let me know what you prefere.

[svein]

Unfortunately I'm absolutely sure. I measured today again.

It is indeed a 1ch variant. I am happy to open it and take a look, possibly re-solder it if its as easy as a broken connection. If its that simple, its stupid to ship it around europe!

But maybe you have some tricks on how to open it without breaking it? haha:)

[ArT]

1CH is very easy, you can open it and take a look but if you do not find anything I'll just sent you new unit without sending your back. Each unit is tested before shipping but who knows, strange things happen Just let me know. Assembling is without any screws, just separate carefuly 2 halfs of enclosure with very thin tool and little force

[svein]

Opened it today and measured 0ohm between the terminals and the soldering points on the print card, so it seems like its dead internally somehow?

Ill send You an email to get in touch.

Thanks again,
Svein

[ArT]

Ok so it's clear. Seems that something is damaged with terminal or connection. Sorry for this... I'm sending you tomorrow new unit, please let me know when you test it. Sent you tracking details via mail.