Re: Mazdaspeed 3
 

Excellent diagram Richard. Do you happen to have the latest diagram for the gen1 MZ3?

Re: Mazdaspeed 3
 

I am not sure what you are looking for, any one of these?

http://www.aquamist.co.uk/forum2/vbu...ead.php?t=2197

Re: Mazdaspeed 3
 

Hi Richard,

Finally got the system up and running and ran into hopefully a small issue. I'm using an over boost fail-safe device that controls the bypass valve which I've connected to the Aquamist system using the Orange wire from the RJ48 connector.

The issue I'm seeing is the fail-safe device is constantly in a tripped state. I believe this is because the fail-safe is triggered by either a 5-12V or GND signal. After looking back through the literature, it appears that the Orange wire is either in a GND or 5-8V state... which basically means the fail-safe will always be tripped.

Should I use the Orange wire with this fail-safe and if not, is there a way to connect to only a high side or low side fail-safe signal?

Re: Mazdaspeed 3
 

you can invert the output signal of the orange wire by swapping FS0 to FS1.

If you want the output to be 0v/8v, you have to remove the CLP jumper. Otherwise it will be 0v/5v.

Re: Mazdaspeed 3
 

Thanks Richard, I've had the system setup as you described above and still a triggered state from the fail-safe.

The fail-safe will also trigger on a GND signal so will a 0V signal trigger the fail-safe?

Re: Mazdaspeed 3
 

If the 0V is causing the fail-safe to trigger, could I set the CLP and FS0 jumpers and solder a resistor on the output signal to drop the run state voltage below the 4.7V threshold of the fail-safe?

Or what might make more sense is to remove the CLP jumper and use a 4.3V zener diode on the output signal. I believe that would result in an approximate 3.7V reference to the fail-safe given the voltage from the Aquamist with the CLP jumper removed is approximately 8V.

Re: Mazdaspeed 3
 

It is completely up to make the output signal to suit your application.
The "CLP" is just a 4.7V zener diode clamp on the 8V (with 270ohm series resistor). No need to repeat. The low signal is always 0V

Re: Mazdaspeed 3
 

Thanks for the feedback Richard. I'm admittedly not very familiar with circuit design so I just want to make sure my thinking is correct. If I remove the CLP jumper, I will have 8V on the orange wire. If I then put a 4.3V zender diode on the Orange wire, I will have a 4.3V drop across the diode which leaves me with 3.7V at the fail-safe.

Do I need a series resistor after the diode to limit the power going to the diode, or is the current on the orange wire small enough that I don't need to worry about it?

Basically the circuit would look like:

Aquamist - Orange Wire - Zener Diode - Resistor? - FailSafe Wire - Failsafe

Or, do I simply keep the CLP jumper and just add a small 2V or so Zender diode to the Orange wire to drop the voltage below 4.7V?

Re: Mazdaspeed 3
 

You can put a series zener diode to drop the voltage. Why is third part system so complicated?

Re: Mazdaspeed 3
 

No clue. I think they tried to cover all of their bases by having two trip values but it just makes things more complicated.

Thanks for all of the help, it is very much appreciated.