Im trying to setup a pyrometer /EGT for a diesel engine and have just discovered i can only measure up to 500C using 5v, when i realistically need to be around 1000c (need to see around 1800f). Im kinda at a blank at how to approach this. If anyone has a board layout with a parts listing to what I have to build to do this, i would greatly appreciate any help. BTW im going to be using a Type K thermocouple with a 1300c rating.
would it be simpler to build a 10v power supply for the ad595, then half the voltage on the signal wire, then multiply the value in the code by 2?
I only took a quick look at the AD595 but it looks like they recommend a higher
voltage supply for temperatures above 500degC. I am a little surprised that they
didn't have an application hint that shows how to adjust the gain. Maybe I missed
it. There may be other amps with an adjustable gain.
I am not sure how you would multiply by two to determine the reading.
With a 5V supply all readings above 500degC would output 5V.
(* jcl *)
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well i was talking about halving the voltage on the signal wire from the ad595 with 10v running to it. but now that i think about it, i dont think it would work for values under 500c.
IIRC the function is 10mV/DegC. Dividing the voltage output of the AD595
should work for all temperatures. The only problem is accuracy.
(* jcl *)
ill be ok with +/-3c accuracy, this leads me to my next question, does anyone have an example circuit that i can reference to build my divider? or is this a simple IC i can integrate?
The divider is just two equal value resistors in series. I would use values between 2K and 10K. You will probably want 0.1% tolerance unless you plan to calibrate the
divider.
AD595 OUT --10K-- * --10K-- GND
The divided output is the point between the two resistors.
(* jcl *)
so rA and rB should both be 10k?
from the divider calculators ive used, i thought I only needed 2 330ohm resistors.
Then again, I am very new to this.
I've got a working EGT meter, and I use the same IC with an type K thermocoupler, and a DC-DC converter.. 5V -> 15V
On the output, I've got a divider-circuit, so that max output(input to Arduino) is 5V.
Works like a charm!
Mind sending me the layout? im assuming you multiply the value of the signal line x3?
was looking at this http://www.trcelectronics.com/Cosel/suw30515c.shtml
I've connected the AD595 to +15(from dc-dc converter) and GND.
Something much like the one you linked to, only my converter is only +5v to +15v and GND..
The divider circuit is only three 2kOhm's in series.
Theres no layout, just protoboard..
The DC-DC is a "TEN5-0513"
https://www1.elfa.se/data1/wwwroot/webroot/Z_DATA/06958615.pdf
Do you remember where you bought it, id perfer not to order it through a Chinese website, which is the only place i can find it.
so rA and rB should both be 10k?
from the divider calculators ive used, i thought I only needed 2 330ohm resistors.
The value does not matter too much (1) as long as they resistors are equal and (2) as long as they are not too high or too low. Too low and you load the AD595. Too high and the A/D accuracy and measurement time suffer. 2K-10K is a safe range.
An easy way to get a voltage doubler (or tripler) is to use a switched capacitor IC.
You can get these in DIP packages and the only other parts (for a doubler) are caps.
For a tripler you need a couple of diodes. I like the ADM660. There is a doubler schematic in my LCD interface datasheet at Loading...
In my circuit I put 3.3V in and get 6.6V out. If you put 5V in you will get 10V
out. A tripler schematic would be in the ADM660 datasheet.
(* jcl *)
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Perhaps im blind, but i couldn't find the tripler circuit layout in the data sheet. Does anyone have an example? Ide be much happier to feed the ad595 15v to get the highest readable temp, but then that would leave me with 15v for the signal wire, which i have no idea how to reduce to 1/3rd voltage.
I couldn't find the tripler schematic either 
I must be thinking of a different part. Unfortunately I can't seem to find the datasheet with the schematic.
On the divider to get 1/3rd the voltage you would make Ra twice as large as Rb.
(* jcl *)
Awesome, now i just need to find a tripler IC that doesn't cost me 15 bucks. 
Any ideas?
Why don't you just use the supply voltage from the vehicle? Assuming your alternator is working properly you should be getting 13.8-14.4v.
There's also this:
http://toysdownunder.com/adjustable-regulator.html