Are there not off the shelf engine monitors ?
I thought all this information was on a bus system now days ?

Are you looking for of the shelf solution, modules you can use like the volt meters, or are you up to doing a bit of circuit building,

Looking at the inputs,
"all" you have to do if they are over the range your equipment can measure is to attenuate the signal, a bunch of resistors would do that.

There are many ADC's with mux's on the inputs,
examples would include MCP3208 through to chips such as ADS8588S

Alternative could be an arduino
https://www.pjrc.com/teensy/
with an analog mux on the inputs,

More than anythign I would say it depends upon your level of expertise, and expectations

Thank you for the response!

We use these engine monitors daily. But we cannot actively read raw values from each sensor or actuator. almost all of the sensor values are HW into the ECU, and only a few of them communicate via CAN, sadly.

ECUs can behave very strangely if they are broken, still everything might work fine so the customer dont notice.

So in the event of suspicion to whether a ECU is defective or not, We need to monitor actual voltages supplying various sensors. Just in order to know if in the case we do have error codes, that they are real, and not due to ECU failure.

Being that all I need is to have a simple way to actively see voltage for a specific sensor, or compare sensor feedback etc, while engine is running, I dont want to bother with studying all this and making it my life`s work. first time around anyways

 

The problem is that what the application requires, really, is 110 DIFFERENTIAL inputs and then a selector to feed the selected input to one of three amplifiers feeding three or more A/D converters, one optimized for each voltage input range.
But there is already a product made that gets most of the way there. That is a 110 input front-end made for ultrasound scanners. That has been a product for a couple of years, at least. And it already presents the digital voltage reading and the channel ID to a computer input.

Do you have a product name or a link for this?

 

Thank you for replying!
Concidering space here. How much space would you suppose this setup would require? Given that I will need more than double the amount of inputs than currently in your diagram.

Do I understand this right?
The 5 multiplexers, transmitt the signal from tot 40 inputs. and the 6th multiplex recieve these signals and transmitt this to a IO? Will I be able to simultaniously monitor 5 inputs from the same multiplex, on my screen? Will this work, as all 110 of the inputs I will monitor, is constantly powered, and constantly changing.
BR
Fredrik

Unless each input voltage needs to control any device, otherwise using scan method to read the input voltages and display them is the better way to do.

1. Input voltages 12V and 0~30V through 10K + 2K voltage divider to get
Vd(0~5V) = Vin(1/6)
Vd = Vin(2K/(10K+2K)).
(You will be need to use 10Kx110, 2Kx110, if you can find some network resistors, maybe you can reduce the space, the resistor in the network resistor should be independent)

2. Vd to the input port that the circuit I designed, you can use 74HCT4067x3 and 74HCT4051x1 to get 56 input pins.
(You will need another 74HCT4067x3 and 74HCT4051x1)

74HC138 was used for select IC1~5 which one should be works, maybe you can use 74HC139 to replace 74HC138, but it is depends on how the 0~55 and 56~110 input pins work.

74HC/HCT139 --
Dual 2-to-4 line decoder/demultiplexer.

3. You can using 6 pins from Arduino I/O port to select one of 55 input pins and using one ADC pin to read the voltage that the pin you selected, and then you can through the Arduino USB(RS332) to communicates with the computer or laptop.
(Except the Arduino, you can choose some other MCU boards that you like)

4. On the computer side, you can multiple 6 times to reverse the Vd voltages which the input voltage through the voltage divider.

When you want to display the voltages on the screen then you can display Vin 1~55 for one page, and Vin 56~110 for another page.

 

Many years back I was part of a program for developing an electronic engine fuel control system. I was in the development tool creation group and we did need to provide monitors for every sensor and every output signal. That was a lot of connections. It could lead to a large collection of cables and connectors, and quite a bit of hook-up time needed.
So I offer a suggestion, the method that worked for us, which was to have inline tap connectors at the module rather than connectors all over the engine compartment. The hook-up is simpler, unplug the cable from the module, plug in the adapter, and then plug the engine cable into the adapter. The added benefit is that this also evaluated the integrity of the sensor connection wiring, as well as the actual sensor.
At the tester end then there were just a few multi-pin connectors, and just a very few larger cables.
Inside the tester we had rotary switches to select which sensor was connected to the meters, which were standard digital meters. Several meters handled the different voltage ranges, and a frequency counter checked the frequencies. A much simpler arrangement that did not need much calibration at all. And the box was simple to copy, since we needed three of them.

 

There are many ADC's with mux's on the inputs,
examples would include MCP3208 through to chips such as ADS8588S

Maybe the output speed of MCP3208 is too slow for this application, because its output was used Shift Register and it will be in series output, and this project need too many input pins.

 

Maybe the output speed of MCP3208 is too slow for this application, because its output was used Shift Register and it will be in series output, and this project need too many input pins.

Your right @ScottWang,
we don't know what frequency of change the OP is asking to measure,
I'm guessing fairly slow as the Op is talking about using meters,
hence pointing out the possible range of options they could be looking at

 

Im actually starting to belive that 55 mini DC voltmeters 10x23mm, and one 2pos switch for each meter, is the simplest way to go with this XD

Some of the more important sensors (e.g. for crankshaft position) will have rapidly changing outputs. DC voltmeters (or your eyes!) won't be able to follow the changes accurately. I think a better option would be a multi-channel oscilloscope, with the channel inputs fed by any multiplexing/selecting/conditioning arrangement deemed necessary.

 

Back in post #24 I suggested manual switching and several meters, one for each range, plus a frequency counter for those sensors that provide a frequency output, like fuel flow and air flow. %% meters would be way too many. And consider that the device is intended to be a service tool, not a lab instrument. I created one for the company that I worked for back in 1975, and it did get used by mechanics, not electronics masters.