I was asked to investigate an intermittent fault with this device. It makes a nice #NameThatWare challenge. Can you guess/deduct what it is?

Please use a CW for your answers. Googling is fair game. Please don't just write a single word as answer, instead describe your observations and deductions.

@cccpresser ok. Very wild guess: probably the Audio codec is used as AD/DA converter for some $Measurment application. The 16bit ADC and the 2 OP Amps could be part of a compensation circuit. Since I didn't trace out the Codec's output pins, my guess is that it more or less feeds into the sub d connector and takes back feedback signal taken from there. due to the overall form factor of the PCB it is probably part of a DIN Rail mountable PLC expansion/connector. I settle for a...

@werdahias Nope, not even close.

@cccpresser sort of lock-in-amplifier, e.g. for reading out strain gauges. This is also a bit supported by only part of the pins on the connector being used and (probably?) being fed through ferrite.

I am probably completely wrong. But I am looking forward to the solution...

This was good fun 😊

@dickenhobelix I think the amplifier part is correct. I have not further reverse-engineered the thing, but I had the same conclusion and its highly plausible based on the type of device and measurement principle.

The guess is wrong though.

@cccpresser oh, nevermind it's not a ferrite, it's just glue. Welp.

@cccpresser second and last guess would be a circuit for reading a resolver https://en.wikipedia.org/wiki/Resolver_(electrical)

@cccpresser the db9 is either rs232, can, or rs485. there’s a header labeled sensor, and the fpc cable might be going to a display or hmi module. looks like industrial design from between 2000 and 2010. the lack of obvious mounting holes or slot surprises me. the single button on the short side makes me think this isn’t an addon board to a larger equipment, but a standalone device? maybe a field sensor / transmitter.

@dickenhobelix nope, not a resolver.

@uint8_t
Awesome, you got a lot of things right!

rs232 or rs458 ✅
industrial design from between 2000 and 2010 ✅
display or hmi ❌
standalone device ✅
field sensor / transmitter ➖

@cccpresser DB9, compact form factor, layout, high quality board + components -> DIN-rail-ish industrial automation, measurement automation or telco equipment
I see Burr Brown + Analog Logos on ICs, some LF A/D, measurement stuff maybe

The PCB was taken from this Bronkhorst gas pressure controller.

The FPC goes to a 2nd board that has the RJ45 jack for the 'FlowBus' connection (not visible in this picture).

@cccpresser ok, that's definitely an interesting piece of gear. Do you know the measurement methodology?

@dickenhobelix temperature drift.
Heat part of the gas in the so called bypass, measure the heat transfer.
You can find pictures online if you look for "mass flow controller".

@cccpresser I see. Though I am a bit irritated what the Audio codec is used for 😅

Luckily enough I am not a hardware person 😂

@dickenhobelix i assume its a lock-in amplifier. That is magic which allows to differentiate the signal from the background. For that you modulate the excitation signal.

I have never seen it for temperature stuff, since that is "slow".
But its just a guess anyway.

@cccpresser
I used to work for a competitor of Bronkhorst. A lot of these types of meters use two coils of platinum wire around a small tube (capillary). Enough current is put through them so they heat up, and simultaneously to make a voltage drop to measure the resistance. A Wheatstone bridge is used to get an output. This is put through some kind of calibration curve to make it accurate; every one needs to be individually adjusted for how it will be used. I think bronkhorst used a three coil design, where the middle one is heated and the resistance difference between the first and last is measured.
Let me know if you have any specific questions I might be able to help with!
@dickenhobelix

@cccpresser the Japanese microcontroller is pixelated so some kind of Hentai rendering unit?