Is it possible to simply share the the signal/voltage from standard 0-5v temperature or resistance sensors between the ECU and the dash? In my case it is about oiltemp, CLT, Pre-IC temperature and fuel level in an old VW Golf MK2 dash. Would it be possible to just use the same sensor ground and split the 0-5V signal? Or would this result in wrong sensor values?
Hope someone could help…just want to avoid that i have to install all the sensors twice.
Basically it is possible, but i learnd it comes with issues.
In this thread the topic was discussed:
U should choose a main ECU for each sensor and connect sensors ground + voltage supply to it and just rout the signal line to the second ECU (to a high resistance input). Both ECUs should have a common main ground or wire to connect both grounds as short as possible (same for 12V supply for both ECUs). Wired like that the main ECU will have a good reading of the signal…the second ECU will have a slightly corrupted reading depending on ur grounding situation.
If u connect sensor grounds of both ECUs or try to connect supply voltage for the sensors of both ECUs u will corrupt the signal for both ECUs.
But i think u should try to avoid doing it like that…just if u don’t have an other option. Best way would be share signals via CAN.
Thank you for your reply…i give it a try…will take some measurements and see how bad the influence is on the sensor values.
If im not happy with the result, i will go for CAN Bus.
In theory, is it possible to catch the sensor signal via Analog Input (on the EMU Black) and send/copy this value via CAN Bus to an AUX output on the Switchboard V3? Like a pass-through…If so, i could feed my dash with the needed values without having every sensor twice. This way i’m just wasting some AUX Outputs.
What dash do u have?
No it is not possible to forward the signal by useing an AUX output. The aux outputs of EMU and Switchboard are switches to ground. U need an analog output to output +. Not many ECUs have this.
But this is also not a real solution…u basically have the same issues like in sharing the sensor signal directly, depending on the grounding situation and currents flowing through the ECUs. Analog signal transmission is just not good.
You can use an aux output and PWM to control a 0-5V signal. I’ve tried it and the Black really isn’t the best hardware for this, it can do max 250 Hz which isn’t enough and requires adding an RC circuit to stabilize the signal to the gauge. There also isn’t enough PWM tables and the tables can’t use all those sensors as axis.
Other ecu brands do this better, so I agree this isn’t an avenue worth going down.
Better option imo is to accept some loss of accuracy for things like the fuel gauge and run two sensors for the more critical stuff. I also highly reccomend CAN based gauges, though there are not always period correct looking. Check out Speedhut gauges
Thank you for your advices - i see there is no clean way out😅. At least not like the way i was hoping for. I will just double the critical sensors and make some compromises.
Thank you anyway for your your support and for sharing your knowledge. This really helps Newbies like me👍