Output only triggers when set on Inverted

General Topics for configuring, operating and tuning the Megajolt. Also see the <a href="http://www.autosportlabs.net/MJLJ_V4_Operation_Guide">Operation Guide</a>

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Brocky
Posts: 2
Joined: Mon Jan 13, 2014 9:34 pm

Output only triggers when set on Inverted

Post by Brocky »

Hi there,

Over the weekend I have been setting up the AUX Input to read from one of the GM water temp sensors I got off the site.

I had to invert the values in the scaled column as the on screen gauge reading went down as the temp when up, regardless of the polelarity of the sensor wiring. Note I am grounding one of the sensor wires to the block. This works in terms of read out but did need a little offset in the figures to calibrate.

Q. I am trying to use one of the Outputs to trigger a cooling fan relay, based on a threshold from the AUX Input, unfortunately I can only get any of the outputs to provide ground (little green lights) and start the fan in the inverted mode setting, and seems to be regarless of whether the gauge value is higher or lower than the threshold set. (i.e the fan starts when the invert drop down is selected and downloaded to the module). to stop it i have to then select normal and download setting to module.

I also noticed that the relay when not recieving switching to ground from the mj, the mj seams to be recieving + ve from the solenoid, and powering up.

Would introducing a diode in the output to the relay help ? Have you heard of this before ?

Note the outputs work ok based on load etc.

Note 2. This is all with just the ignition on, i.e. motor not running

Many thanks

brentp
Site Admin
Posts: 6277
Joined: Wed Jan 24, 2007 6:36 am

Post by brentp »

Hi,

What kind of behavior do you see on the actual reading from your sensor? you can see this when you enable the Aux gauge in the view.
Brent Picasso
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Brocky
Posts: 2
Joined: Mon Jan 13, 2014 9:34 pm

Post by Brocky »

brentp wrote:Hi,

What kind of behavior do you see on the actual reading from your sensor? you can see this when you enable the Aux gauge in the view.
Hey BRent

As you suggested, I started the motor and everything work as it should....problem was it was late in the day and too late to run the motor (noise wise )

I need to calibrate the sensor a bit more though as the readings are far from linear.....

Also I cut the pre ignition power from the relay which stopped the unwanted power up to the unit. Won't be able to run the fan after turning off the motor though but perhaps a diode will fix that ?

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