I doubt you would loose 50 degrees along the length of the van. You'd be surprised how good they are!
I know a twit who used the wrong thermocouple, K type when he should have used N type. The Marmite hit the fan, we overcooked some exhaust manifolds by 100'C - we read 600'C with an actual of 700'C, unbeknown to us the controller was N type only. Modern digital ones you pre programme according to what you have
does seem like a big loss....but then again, you're looking at millivolt differences corresponding to a relatively small temp range ... Sounds like it's your department though
The extension cable are different from the cables on the thermocouple, that's for sure. They are weird things, no power involved to work the gauge.
IIRC thermocouples work on temp differential between two conductors which instigates a tiny electrical charge...this is what's monitored by the guage...there's obviously more to it than this but my O'level physics is a bit rusty Mork will know more...he sounds like a boffin
its usually those millivolts what leave you puzzled! http://www.ncode.com/fileadmin/mediapool/nCode/brochures/Brochure_Material_Testing_EN.pdf page 2 on the link has one of our samples cooking nicely (the brochure is what I am involved with)
you'd've got on with my old fella...he used to devise tests an testing equipment for textiles and fibres...different field, but similar mindset he did loads of stuff on 'rip stop' after the war and then fire resistant fabrics that actually become more resistant the hotter they get....now industry standard...all good stuff
I'm not clicking that link. i'll try some trial and error and see what happens - beats thinking (if it works).
I'm only feet away, but it's too dark in the engine hole and torch in the other unit. I remember joining white to white...
@zed We have a roll of J Type compensating cable here in the Lab; if you want a couple of metres, shout up!
@zed The VDO system comes with a short thermocouple (the 14mm plug ring & 2 sender wires) which is about 30cm long. IIRC it is then possible to connect 'ordinary' automotive cable & run this back to the cab mounted gauge. There is no requirement to use special thermocouple extension wire to run the length of the bus. The connection to normal cable on Chip is outside the engine bay just under the tin by no3. I just fed the thermocouple through & used choc-blocs! The only 12v you need in the cab gauge is for the light. The above said, there are issues with accuracy and ambient/engine bay temperature affecting the reading but you soon get used to reading the gauge as a comparison, not as an accurate calibrated instrument. However, I think it's a k type so whether this makes a difference, I'm not sure. BTW, I'd recommend clearancing the ring slightly so it doesn't hang on the plug threads as you take the plug in & out. The angle of the dangle of the plug & the bends you have to put in the ring to get it to seat mean it can sometimes be a bit tense at service time if the ring is too tight.
Whaaaaatttt????!!! Bugger, that was a waste of a few quid then and maybe made it work less well if I really have cocked up the extending.
