this page has a picture of (some) of what’s inside an EDM 700
I can’t see a link there @alioth but I have seen the internals of the “classic” EDM700 and it was all PTH, 1970s tech, probably a Z80 running at 4MHz or some such. Same as the Shadin Microflo actually. I have one of those somewhere… stand by 
Indeed, this page has a picture of (some) of what’s inside an EDM 700 – typical late 70s/early 80s pin through hole construction on what looks to be a 2 layer PCB (although there are some SOT23 surface mount transistors on there too). Compare to the picture of the construction of the Garmin handheld GPS beside it.
I am working on a hobby project right now and it is really obvious that with a suitable OLED dot matrix display on the front one could make an EDM700 replica, no more than 5cm deep. I already have the sensor interfaces sorted (all eight thermocouple types, pt100, pt1000, ad590). It would be a few weeks’ work to do a prototype. The reason why an EDM (etc) is so deep is because it uses 1970s components and design practices.
Of course you could never install it (unless you had an RV or some other non-cert plane)
there was recently a $400 rebate on EI CGR30P and if you bought the combo 2 screen set, the rebate was $800.
Crazy deal. It expired but EI told me they plan to relaunch it in 4 months. I’ll be waiting for it.
I had a JPI 830 fitted about 4 years ago and it has been trouble free and very beneficial.
I had Carb Heat, Fuel Flow, Battery Volts, Oil Temp and Pressure, and RPM, some
duplicating the factory fitted gauges but adding the possibility of software limits and
hence a warning should a problem start to develop.
The JPI 830 provides for an external warning light or two which can be put in a very prominent place for the
pilot and thus if any max/min value is exceeded one cannot miss the fact. You might not be offered this – I
wasn’t and I had to go back and get it fitted.
A Battery volt option might seem over the top but can be very useful. One can easily do a regular test to see
battery volt decay (taxi-ing) with various loads with ALT off and thus give consideration to whether you would like
a new battery.
One minor problem I had with the installation was that my aircraft had a single CHT gauge and thus an probe
existing and the JPI 830 probe was piggy backed onto this. This is a mistake as a later comparison with
the other 3 CHTs reasoned me to think that all 4 CHT probes must be fitted identically and thus I had to
remove the old probe and ‘in_op’ the old gauge. To my mind this should have been obvious in the first
place but you live and learn.
My reason for fitting the monitor was that my engine was approaching 1000 hours and I thought it
would be money well spent knowing more about my diminishing asset.
We’ve recently installed a JPY EDM 830 and love it. Good, clear colour graphics, plenty of information but can be customised to prevent overload, and does all the things you’re after – and then some. Only slight beef is that the buttonology is a bit clunky given there are only two buttons – LF and Step – which, between them in various combinations, have to do everything. You have to learn these combinations by experience (and a cheat sheet supplied by JPI helps) but eventually it all comes together.
We upgraded in (financial) stages with our C182S to a GTN, G5, ADSB-Out, second 8.33, portable O2, Pilot Aware and now the EDM 830. We’re basically just a couple of devices short of pretending to be a jumbo jet, in fact. Works a treat.
Thanks for all of those – the MGL kit looks the most interesting at the moment (and I like the idea of having the data acquisition box remotely mounted – less wiring behind the panel etc).
The CGR 30 is about 80mm deep (excluding the connectors) and there’s a separate data acquisition box which you can shove anywhere.
Worth a look.
