GRT CS-01 current reversed

Bubblehead

Member
Joined
Oct 3, 2011
Messages
37
I had a GRT CS-01 sensor go bad. I ordered one from GRT and it came in a soft-sided mailing envelope and the leads were bent over and the connector broken. I called and they sent another in a box. I installed it today with the arrow in the direction of current flow which duplicated the previous sensor.

It powered up fine but when I started the engine it showed negative amps. It is on the B-lead of the alternator so that did not make sense. I turned on a lot of loads and the current number got bigger (but more negative) and voltage stayed correct so it appears the alternator is putting out current properly but the sensor is reversed.

It is a PITA to reverse the sensor. I am hoping I can change something in the setup or do a custom sensor setup to reverse the reading.

has anyone else run into this? Is there a way to reverse the reading other than flipping the sensor?
 

Bubblehead

Member
Joined
Oct 3, 2011
Messages
37
Would it reverse the display if I changed the engine sensor definition for this sensor by reversing the signs on the coefficients?

ORIGINAL
low_coeff={
c_x4=0
c_x3=0
c_x2=0
c_x1=-61.5384615384615
c_x0=144.615384615385
}

MODIFIED
low_coeff={
c_x4=0
c_x3=0
c_x2=0
c_x1=61.5384615384615
c_x0=-144.615384615385
}
 

Bubblehead

Member
Joined
Oct 3, 2011
Messages
37
Would it reverse the display if I changed the engine sensor definition for this sensor by reversing the signs on the coefficients?

ORIGINAL
low_coeff={
c_x4=0
c_x3=0
c_x2=0
c_x1=-61.5384615384615
c_x0=144.615384615385
}

MODIFIED
low_coeff={
c_x4=0
c_x3=0
c_x2=0
c_x1=61.5384615384615
c_x0=-144.615384615385
}

Or maybe reverse coefficients c_x1 and c_x0 like this?
ORIGINAL
low_coeff={
c_x4=0
c_x3=0
c_x2=0
c_x1=144.615384615385
c_x0=-61.5384615384615
}
 

Bubblehead

Member
Joined
Oct 3, 2011
Messages
37
Changing the signs of the coefficients seemed to have worked. I tried it this morning and other than needing to adjust the offset for the no-loads setting I think I'm in business. As I added loads the amp display changed about the right amount.

If this happens to you try changing from "ORIGINAL" to "MODIFIED" in Reply #2" above.
 

kurtfly

I love flying!
Joined
Jun 21, 2014
Messages
211
You are correct to just change the sign's on the two coefficients as in your first reply. Just remember to save off your sensor definition file (SFG) so you can just re-load it after you do a firmware update.

Kurt
 
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