Data down the CAN when an ecu has no logging enabled?

[Chris Wilson]

Will a *00 series ecu send data for external logging down the CAN BUS even if the ecu in question has no logging enabled? I'd try it for myself, but my M800 ecu does have logging enabled. I am buying an M600 for another project and it has no logging enabled, I am wondering if it will still output selected data channels via a Custom CAN set up for logging by an external logger? Thanks.

As an aside, my M800 has GPS on the serial input, and I have enabled Custom CAN to send GPS Speed, Lat and Lon, GPS Time, Sats Used and Sat Quality, (as well as a host of other stuff). My logger sees Lat and Lon, does the maths and gives GPS coordinates, it also sees GPS Time correctly. It sees nothing at all for GPS Quality and Sats Used. All other data channels are read correctly and reliably. Is there anything "funny" about the data for these two channels down the CAN BUS?

[IDP]

The ECU will send the data on CAN with or without logging.

Not sure on the GPS question though.

[Holmz]

...
As an aside, my M800 has GPS on the serial input, and I have enabled Custom CAN to send GPS Speed, Lat and Lon, GPS Time, Sats Used and Sat Quality, (as well as a host of other stuff). My logger sees Lat and Lon, does the maths and gives GPS coordinates, it also sees GPS Time correctly. It sees nothing at all for GPS Quality and Sats Used. All other data channels are read correctly and reliably. Is there anything "funny" about the data for these two channels down the CAN BUS?

I think that the #Sats is an 8 bit word (or maybe an 16 bit, but only one of them).
The others are 16 bit (or maybe 2 of the 16 bit words) - whatever they are is twice the size of the Lat or Lon.
Do you have that right?

[Chris Wilson]

Getting the latitude and longitude out of the M800 and into the logger was easy, but the maths has proven complex (at least it was complex to me, I got a kind friend to help out a lot...). Jamie Augustine at Motec was very helpful and felt that it should be straightforward. Negative latitudes didn't seem to be accounted for though, which at one stage I put down to Motec being in Oz and them not having to worry about certain latitudes further north Here is what he felt would be the required format into the logger viewing software:

"You just need to place the high word to the left of the Low word, without
any multiplication, division or anything.

You can then put the decimal place at the 7th number in from the right.

Example:

The GPS Lat and GPS Long are just split in 2, nothing more challenging that
that.

GPS LON HW is the High word component.
GPS LON LW is the Low Word component.

Eg
144.9688203
Is
HW is 0101011001101000

LW is 0111110010001011

Put them together


01010110011010000111110010001011
= 1449688203

Divide by
10000000

Gives you

144.9688203

This is the GPS Long value."

I was getting wild results for coordinates until I added maths into the logger, to combine HW and LW so:

Combine GPS Longitude: ((if('GPS LON HW'>32767,('GPS LON HW'-65536),'GPS LON HW')*65536)+if('GPS LON LW'<0,('GPS LON LW'+65536),'GPS LON LW'))/10000000

Combine GPS Latitude: ((if('GPS LAT HW'>32767,('GPS LAT HW'-65536),'GPS LAT HW')*65536)+if('GPS LAT LW'<0,('GPS LAT LW'+65536),'GPS LAT LW'))/10000000


GPS Latitude: if(('GPS LAT COMBINE'>0.0),((('GPS LAT COMBINE'-floor('GPS LAT COMBINE'))/0.6)+(floor('GPS LAT COMBINE'))),((('GPS LAT COMBINE'-ceil('GPS LAT COMBINE'))/0.6)+(ceil('GPS LAT COMBINE'))))

GPS Logitude: if(('GPS LON COMBINE'>0.0),((('GPS LON COMBINE'-floor('GPS LON COMBINE'))/0.6)+(floor('GPS LON COMBINE'))),((('GPS LON COMBINE'-ceil('GPS LON COMBINE'))/0.6)+(ceil('GPS LON COMBINE'))))

Without these functions negative values were incorrectly shown, and Google Earth overlays were thousands of miles off.

Now, tell me I have missed something obvious and all this was unnecessary I can only assume i2 does something similar, plus some neat filtering, under the covers? Unfiltered the above data is a bit ragged when viewed as a track map. Unfiltered overlay, taken via GPS CAN from my M800 and rendered in my GEMS DA99L2 logger and GEMS GDA software, the maths functions were done in the software, but now I am doing them in the logger itself, same result:

http://www.gatesgarth.com/GDA/newrock.kml

[Chris Wilson]

The ECU will send the data on CAN with or without logging.

Not sure on the GPS question though.

Thanks, that's good to know, cheers.

[Chris Wilson]

I think that the #Sats is an 8 bit word (or maybe an 16 bit, but only one of them).
The others are 16 bit (or maybe 2 of the 16 bit words) - whatever they are is twice the size of the Lat or Lon.
Do you have that right?

This is my logger set up for scaling and stuff. I will have a play with the Sats used and sats Quality settings, thanks for that. I wonder if Motec supply all this info in some sort of spreadsheet, a pal was showing off how good his Bosch ecu stuff was and took delight in showing me this in the instructions pdf.

Logger setup: http://www.gatesgarth.com/GDA/data.png

Bosch data: http://www.gatesgarth.com/GDA/bosch.png

[Holmz]

I think that the #Sats is an 8 bit word (or maybe an 16 bit, but only one of them).
The others are 16 bit (or maybe 2 of the 16 bit words) - whatever they are is twice the size of the Lat or Lon.
Do you have that right?

This is my logger set up for scaling and stuff. I will have a play with the Sats used and sats Quality settings, thanks for that. I wonder if Motec supply all this info in some sort of spreadsheet, a pal was showing off how good his Bosch ecu stuff was and took delight in showing me this in the instructions pdf.

Logger setup: http://www.gatesgarth.com/GDA/data.png

Bosch data: http://www.gatesgarth.com/GDA/bosch.png

Chris,

The lat or lon are real numbers, so you divide my something and get the decimal point in the right spot. The #sat is an integer, so 0-10 or maybe a few more (usually I have 6-9) - probably 255 is the limit. Quality is also probably just a HW or just a LW (but half a HW+LW).

[Chris Wilson]

Hi Holmz, so are you saying all my maths functions are not necessary? Two of us, the "other one" being very clued up on this stuff, failed to get proper data without adding the maths, but I have to say it seemed cumbersome.

[Holmz]

Hi Holmz, so are you saying all my maths functions are not necessary? Two of us, the "other one" being very clued up on this stuff, failed to get proper data without adding the maths, but I have to say it seemed cumbersome.

You do need it for the Lat, Lon - as those are double words to get the precision.

I am saying that you probably do NOT (or may not) need it for the #Sats and the quality.
The #Sats is most likely an integer 0,1,2,3.
And the quality might be a real number (12.3) but probably not a long word length.

[Chris Wilson]

OK, thanks Holmz, so how should I set the "Gain" column for reading Sats in Use and Sat Quality? Options in screenshot linked below.

http://www.gatesgarth.com/GDA/bits.png