EM40 suitability

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greenamex2
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EM40 suitability

Post by greenamex2 » Fri Feb 06, 2009 8:26 pm

Just being looking at the only EM40 documentation I can find on the web site (the pinout diagram) and want to check that it is suitable for my application -

4 cylinder, two injectors per cylinder (upper and lower)
Coil on plug
Fully sequential
VR (ie NOT hall effect) crank and cam sensors
Fuel and oil pressure sensors

What puzzled me is the pinout diagram only refers to four injector outputs, is that because other pins and 'double up'?

I've tried to use the existing software to work out the answers but there is no 'template' for the EM40 and the software give me a headache (bring on V4)!

Out of interest what is the difference technically between EM36 and EM40? Is it just packaging and pinouts or does one have a better processor etc?

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RickS
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Re: EM40 suitability

Post by RickS » Mon Feb 09, 2009 2:17 pm

Hi

The EM40 will do everything you have mentioneed but it will use timing inputs and map signal inputs in order to drive the injectors (these pins can have there function changed in the software) obviously you will loose the functionality of these (MAP 2 and Timing input 3) And you will be using 12 of your 14 high current drivers from the ECU. This would only leave you with enough to drive an active throttle OR and idle motor and another PWM device.

The EM36 uses exactly the same processor and Firmware but has far more drivers availible, 14 high current + 6 dedicated ignition drivers, so in this case it would be a better option as it is more flexible.

Hope this helps
Ed

greenamex2
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Re: EM40 suitability

Post by greenamex2 » Tue Feb 10, 2009 7:54 pm

OK, another dumb question.

HOW do I feed in a oil pressure and fuel pressure signal to the ECU, translate it into something useful and then add it to a datastream?

There doesn't appear to be a 'pressure' option.

Thanks.

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RickS
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Re: EM40 suitability

Post by RickS » Wed Feb 11, 2009 11:12 am

Hi,

The EM40, like most GEMS ECU's has configurable inpiuts and outputs. So if there something you don't need, like rotor air out temp for example, then you can use this as an oil pressure input depending on what sensor you have will depend on if you need pull up resistor needed ( a breif modification to the wiring loom which widens the readable range of the sensor) We can provide diagrams of this, it's not a complicated service.

To send it out on the CAN Simply select it in the Telemetry window within the software.

Does this help? If not please let me know.

Thanks
Ed

greenamex2
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Re: EM40 suitability

Post by greenamex2 » Wed Feb 11, 2009 11:19 am

For info I've now switched to an EM36 on your advise but I guess the same still applies.

What I am confused about is how you take the 0-5V signal and convert it into a pressure figure (mbar?) for adding to the data stream. There doesn't appear to be a 'pressure conversion table' in GVW3, unlike those for air/water sensors.

For info the sensor will be a Variohm one so won't need a pull up and the data stream is going to be 'pectel' to go to my PI Omega dash.

Thanks in advance.

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RickS
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Re: EM40 suitability

Post by RickS » Wed Feb 11, 2009 12:58 pm

Hi,

The Scalers and offsets in the options should get you to a reasonable figure which you can relate to mBar but they won't be displayed as mBAr. Your dash should have tables for raw values vs mBAr and this is how it is usually converted. If you are viewing the logged data then DLogg will convert the data for you but at the moment in GWv3 there are no user programable tables. (Soon to be in GWv4 however this won't help with your dash).

Hope this helps
Ed

greenamex2
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Re: EM40 suitability

Post by greenamex2 » Wed Feb 11, 2009 2:03 pm

Unfortunately my dash expects the pressure, not raw, and there is no conversion table.

Probably not making myself very clear (not for the first time).

Referring to pages 23/24 of the EM36 PDF manual, it lists the Analogue and user inputs available. As there is no oil/fuel pressure analogue input you presumably have to reassign a user input to the pins. And as there are no predefined user inputs for oil/fuel pressure you presumably have to pick a couple of other to 'pretend' the required sesnors to then pass on to the data stream.

I understand the conversion (for my sensor bar = (x - 0.5) / 4 * 10, so pretty simple) by I don't understand which 'user input' would be used to 'pretend' to be the oil and fuel pressure input in order to then incorporate into the 'pectel-like' RS232 data stream?

Thanks for assistance and patience on this,

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RickS
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Re: EM40 suitability

Post by RickS » Mon Feb 23, 2009 5:23 pm

Hi,

Yes the EM40 has the functionality to have pins assigned to oil pressure or fuel pressure. These are software selectable and there are many of them. You can then scale the input using the software scalers and offsets. The pectel serial stream will be a standard stream of data in a fixed order and because pectel don't let you change what the dash sees as it comes in you will have to choose one of the existing parameters sent out on the pectel stream and use a defunct item as your oil pressure input. I'm not sure what this would be though as i don't know how the pectel serial stream is constructed.

Hope this helps
Ed

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Re: EM40 suitability

Post by greenamex2 » Mon Feb 23, 2009 5:56 pm

Thanks for that.

Fortunately the Pectel serial stream is documented on a couple sites.

Once I have got the ECU up and running 'standalone' I will have a play, might be able to reduce some duplicate sensors and wiring.

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