I am still stumbling along, trying to figure out the ENGINE TEMP feature. First thing is, apparently it needs to be CREATED under the TOOLS section, not just called in the VIEW section. There are ACD VALUE and VOLTAGE columns; I think ACD is the digital value for the AUX input voltage under VOLTAGE. Apparently can't change these; don't need to. I don't see why I need to know the ACD value. Next column is SCALED VALUE. I would expect this is the gauge value for an input in VOLTAGE column to AUX. The supplied gauge
scale is backwards, and not scaled to the log response of standard sensors (BIG PROBLEM). I would like to see 50 to 250 degrees on
the gauge, I put those numbers in the SCALED VALUE column opposite the voltage a real temp sensor would generate when connected. These seem to have no effect, the gauge is still reading backwards 0-255. OK, from 0-255 to 50-200 might be a different scaling factor, I put in 1.275. This doesn't seem to work, it changes back to 1. I also can't put in scaled values greater than 255; my
air cooled engine might like a 300 degree scale limit.
Since the VOLTAGEs extend beyond limits of my sensor, I enter 50 for values off the cold (high voltage) end and 250 off the warm (low voltage) end. None of this works, the gauge still has the same numbers, still reads backward. What is wrong here? Bruce Roe
MJLJ-V4 Temp Gauge
Moderators: JeffC, rdoherty, stieg, brentp
Hi Bruce,
The MJLJ measures the voltage on the Aux input and translates that to a number.
By default the translation table scales linearly from 0 to 255, where:
voltage = value
0v = 0
2.5v = 127
5v = 255
To use this feature with a temperature gauge you will need to "re map" the default scale to something useful. You can edit each data point on the scale to translate the "raw" measured value to a value that is more representative of what you're using it for.
This table can be edited using this screen (from operation guide)
http://www.autosportlabs.net/MJLJ_V4_Op ... figuration
Since there are 255 numbers you "save" the current calibration and then use a program like Excel or a text editor to plot out all the numbers, then re-load the calibration file.
Once the table has been modified you can "flash" it to the controller and the MJLJ will use this new translation table. This will reflect in the Aux Gauge as well as be useful in the Ignition Correction table.
You're correct: currently the limitations are 0-255 for the scaled value and only whole number scaling is supported.
Hope this helps,
The MJLJ measures the voltage on the Aux input and translates that to a number.
By default the translation table scales linearly from 0 to 255, where:
voltage = value
0v = 0
2.5v = 127
5v = 255
To use this feature with a temperature gauge you will need to "re map" the default scale to something useful. You can edit each data point on the scale to translate the "raw" measured value to a value that is more representative of what you're using it for.
This table can be edited using this screen (from operation guide)
http://www.autosportlabs.net/MJLJ_V4_Op ... figuration
Since there are 255 numbers you "save" the current calibration and then use a program like Excel or a text editor to plot out all the numbers, then re-load the calibration file.
Once the table has been modified you can "flash" it to the controller and the MJLJ will use this new translation table. This will reflect in the Aux Gauge as well as be useful in the Ignition Correction table.
You're correct: currently the limitations are 0-255 for the scaled value and only whole number scaling is supported.
Hope this helps,