Sv: Piggfridekk i-miev

[Poppe]

I wish you the best of luck in finding the documentation !

Meanwhile I'm beginning to think it is a misconception about the diode fuse. There is nothing in the papers that indicates there is any semiconductor involved except for two things: 1) The symbol on the fuse and 2) The company name that someone found where they can be bought (High power semiconductors).

In the case of my fuse which leads equally well in both directions it does not seem likely that a possible internal diode has been short circuited but the fuse itself is still in good order. Further it says that the polarity is N/A in an installation and I can not see any indications in pictures or on my diode that there should be a polarity on it.
Further more this a an HRC component meaning it can separate high currents once it has blown. In this case 950A. What would a diode do there ?
If you did not dig in to diode to measure in your GF's car, would it be possible that you measured some other protective diode accessible from the outside ? Could there be a "wrong polarity diode" at the input of the heater to make sure the fuse in the PSU blows and not the expensive heater ?? 

The manufacturer of the fuse is Eaton which is a very VERY big company and I'm not sure it would be possible to get them to answer such a basic question.

[Warlock]

Yes, I also believe i measured several components in one go, one of them being a diode of some sort, or acting in that way. The only reason i thought it to be in the fuse is the symbol on it, but as you say it doesn't make too much sense...

[BauDemo]

The diode symbol on the fuse is to signal that the fuse is so fast that it is suitable for protecting semiconductor components.
There are no diodes in these fuses.

[Poppe]

Thanks Nikolay
Good to have that cleared out, now its only the rest left 

[BauDemo]

I am not sure how far are you Poppe...
The heater is pulse controlled, and has some electronics inside.
Have you checked that you get 300+ VDC on the heater plug when the car is started?
Maybe you want to write couple of lines to describe what you did - I think I got lost in this fuse discussion.

[Poppe]

Actually I have not yet checked the 370V since the Think, being driven to university by one son every day, has not been home lately until after dark.
In hind sight that is obviously where I should have started if I had red all information here.
Anyway the heater does not work at all since some months and before that it was working sometimes.
I have dismantled the heater and seen it has two heating elements which both are 12 Ohms which seem to be a reasonable value.
When I took it apart I could not dream of the complexity of the electronics I have later learned what is inside the yellow PU. After all, how hard can it be to warm some water ? Obviously very hard !
So the fuse is not gone, the heating elements seem ok and the 370 is unknown. I hope he will be home earlier today.

[Poppe]

Home early today before sundown.
Yes, I have 343V on the outlet for the heater with some 50% SOC.

I also measured from HV minus to the big fuse and there is no short curcuit there through the Power Current Elevator.

BTW is there always HV to the heater when ignition is on ?

How does the control signal from the heater ECU look like ? Is it just a 12V for on and 0V for off ? Cant be that simple can it ?

[Warlock]

It's that simple, the system rapidly turn it on and off, varying the length of how long its on versus how long it is off. This determines how much heat the unit is producing. This is called Pulse Width Modulation (PWM).

[Poppe]

Ok, that simple !

What should I measure when I test the third cable to the heater ecu. Not the on/off or ground but the "trouble" wire.
Is that only a temp probe or something else ?

[Warlock]

Found this as a description of the Error pinout:

"
FAULT_OUT 

Fault output (Open Collector:MAX 10 mA, 50 V), in case of: 
- Overvoltage
- Overtemperature, T >= 80°C
- Fluid flow interruption (Temperature Gradient based algorithm)
- Fluid absence detected (Temperature Gradient based algorithm)
- Intermittent when the temperature is in the right range after (2-3-4) fault condition: the normal operating will automatically reestablish
"

[BauDemo]

It's that simple, the system rapidly turn it on and off, varying the length of how long its on versus how long it is off. This determines how much heat the unit is producing. This is called Pulse Width Modulation (PWM).

If you are referring to the enable pin (HEATER_EN) - this is not true.
In fact turning the heater on and off by using the enable pin is expressly forbidden by MES-DEA. I think they call it "misuse".

[BauDemo]

Home early today before sundown.
Yes, I have 343V on the outlet for the heater with some 50% SOC.

I also measured from HV minus to the big fuse and there is no short curcuit there through the Power Current Elevator.

BTW is there always HV to the heater when ignition is on ?

How does the control signal from the heater ECU look like ? Is it just a 12V for on and 0V for off ? Cant be that simple can it ?

There is always HV to the heater (and the plug next to it) when the ignition is on... (let's make a fast charger!!)

The control signal is either enable or disable. When enabled heater is keeping the temperature of the liquid at a certain level (say 75C). It has internal electronics that do the PWM from the high voltage input. So in reality the max power of the heater is much higher than 4kW (or was it 3), but it averages at approximately that. When the liquid reaches the 75C level the heater is switching itself off, until the temperature goes down with some threshold. And then it is back to ON.

[Poppe]

It's that simple, the system rapidly turn it on and off, varying the length of how long its on versus how long it is off. This determines how much heat the unit is producing. This is called Pulse Width Modulation (PWM).

If you are referring to the enable pin (HEATER_EN) - this is not true.
In fact turning the heater on and off by using the enable pin is expressly forbidden by MES-DEA. I think they call it "misuse".

I understand the heater is a selfregulating system that internally goes on/off depending of the amount of heat taking out of it regulated by mechanical heater settings, but still HEATER_EN must be some kind of signal (that I might not have for whatever reason). So If I measure this signal what should I expect to find ?

Where exactly is Mes Dea say its forbidden to use this signal to regulate the heat ?

The control signal is either enable or disable.

I would guess from your comment that its 12V for On and 0V for Off.

Found this as a description of the Error pinout:

"
FAULT_OUT 

Fault output (Open Collector:MAX 10 mA, 50 V), in case of: 
- Overvoltage
- Overtemperature, T >= 80°C
- Fluid flow interruption (Temperature Gradient based algorithm)
- Fluid absence detected (Temperature Gradient based algorithm)
- Intermittent when the temperature is in the right range after (2-3-4) fault condition: the normal operating will automatically reestablish
"

This I only partly understand.
"Overvoltage" I guess from the HV, should be simple to monitor.
"Overtemp" Also easy.
"Fluid flow interruption and Fluid absence detected" If the temperature rises to fast the electronics detect that there is no water or the water does not circulate (broken pump).
"Intermittent when the temperature ..." All faults described here except Overvoltage are self resetting.

"Fault output " Is there a for instance 12V signal on the "Fault Out" and when a fault is detected the heater suddenly starts to draw 10 mA ?

[Warlock]

It's that simple, the system rapidly turn it on and off, varying the length of how long its on versus how long it is off. This determines how much heat the unit is producing. This is called Pulse Width Modulation (PWM).

If you are referring to the enable pin (HEATER_EN) - this is not true.
In fact turning the heater on and off by using the enable pin is expressly forbidden by MES-DEA. I think they call it "misuse".

I was referring to how the heater regulates...

The Heater_EN signal on the other hand is only documented as follows (of what i can find):
"
HEATER_EN (10 mA @ 12 V) 

To enable the heater:   
- The Heater will be enabled with HEATER_EN input to 12 V (Min 8V , Max 18V) 
- The Heater will be disabled with HEATER_EN input floating or to GND
- Available 24V version
"
also of some interest:

"
Fluid Flow Interruption Control 
The Heater can detect a fluid flow interruption (Temperature Gradient based algorithm), in this case FAULT_OUT is activated ( set to GND), and the heater is disabled. To reenabled the device , HEATER_EN must fall from HIGH to LOW state and then rise from LOW to HIGH again, or automatically after 1 min if the temperature return in the normal range.

Liquid Absence Detection 
(Same as above)

General Considerations
The Heater does not accept reverse polarity (semiconductor fuse protected). The FAULT_OUT signal is intended for Heater monitoring only , and can not be used as logical command for other devices of the vehicle. This restriction is due to the delayed activation of FAULT_OUT, in case of detection of a fluid interruption or fluid absence.   
"

https://www.dropbox.com/s/4d6m4ko8y1z9t6w/MES-Dea%20Fluid%20Heater%20RM3_RM4.pdf?dl=0

[Poppe]

Thanks for the info and the pdf !