GRT Current Sensor

MCRider

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Oct 4, 2011
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Germany
Hi,

I am planning to add a current sensor to my factory-installed SkyView and have decided that the GRT CS-01 is easier to install than the shunt. I do not need the 100A range, 50A would be perfectly okay. In theory it should be possible to run the wire through the sensor two times, modify the sensor setup file, get half the measurement range and twice the accuracy. True or not?

Thanks for any help.

MCRider
 

dynonsupport

Dynon Technical Support
Staff member
Joined
Mar 23, 2005
Messages
13,227
Hi,

I am planning to add a current sensor to my factory-installed SkyView and have decided that the GRT CS-01 is easier to install than the shunt. I do not need the 100A range, 50A would be perfectly okay. In theory it should be possible to run the wire through the sensor two times, modify the sensor setup file, get half the measurement range and twice the accuracy. True or not?

Thanks for any help.

MCRider

In theory, Yes :cool: We're working on documenting the process for defining your own sensor to make it doable by mere mortals, but probably not done by the US Thanksgiving holiday.
 

MCRider

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Oct 4, 2011
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Location
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Thanks.

Now I have found the documentation for the sensor. It even suggests to loop the wire to let it pass two times through the sensor in order to get a -50 to +50 A range (or 10 times for -10 to +10A).

Since the polynomial for this sensor is really simple (just a linear component and an offset) I will give it a try...
 

MCRider

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It took a very long time before I could mount the GRT CS-01 with two loops and a modified sensor definition. Now it is done and it works (I still have to verify the measured current with an ammeter but the readings seem to make sense).

Just in case this information is useful for anyone...
 

MCRider

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Just one little problem left: The measurement does not appear in the user log data. The "Amps" column seems to be hardwired to the shunt sensor definition instead of looking at the "function=AMPS" assignment in the sensor definition file.

Or am I making a mistake?
 

MCRider

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I think I might have found it by myself:

Sensor definition:

>>>
sensor={
id=AMMETER HALL EFF +1.5 (GRT CS-01 TWO LOOPS)
function=AMPS
pins=C37_P8 C37_P22 C37_P23 C37_P31
name=AMPS
<<<


dfg file:
>>>
c37_p31={
valid=1
name=BATT
id=AMMETER HALL EFF +1.5 (GRT CS-01 TWO LO
alarm_type=OFF
<<<

Probably the sensor name is too long. In the dfg file it is truncated. I will try a shorter name.

If it does not work I will send the sfg, dfg and a log file...
 

MCRider

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Did a test flight today with the changes - still no amps in the log file.  :(

What is the best way to send you the files (less than 600k ZIPped)? PMs do not allow attachments.
 

dynonsupport

Dynon Technical Support
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First, the config files do only support a name length of 40 characters for the ID. Longer doesn't cause any issues, but it doesn't get used.

As for AMPS being in the datalog, we were a bit off here. It will not be in the AMPS column, that is only for the AMPS shunt. If you are using a hall effect, it will be in the GP X column, depending on which GP you have it wired to. It's in the datalog, but it might just be in a different place than you are looking. In your case, it would be "GP INPUT 13" which is column CU in the CSV, assuming you are connected to pin 31.
 

MCRider

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Okay - but I still can't find it in the data. The sensor is connected to pin 31 but the "GP INPUT 13" column is empty. I have already mailed the data files to the support email address.

Just to put it in perspective: It is not a big deal - I just wanted to help to fix a little bug (it there is one at all)...
 

Dynon

Dynon Staff
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Thanks for the datalog. There is a bug there, it turns out. Things that the system knows about as a special function, like amps, are unfortunately not logged when they're hooked up to GP inputs. We've logged the bug for our engineering team to look into.
 

MCRider

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This is not fixed yet (software 10.1). Is there a chance to get a fix in the next time? I'd like to use the amps in the log file to compare the behaviour of a lead acid and a LiFePO4 battery...
 

dynonsupport

Dynon Technical Support
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Sorry. In all honesty, with only one customer request for this it is not at the top of the list. It's not scheduled for the next release.
 

lgabriel

I love flying!
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Nov 25, 2013
Messages
109
Make that two! Surely there are more of us with dual electrical systems...
 

MCRider

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I'd like to bring that up again (Measurements of GRT CS-01 current sensor not showing up in log file). As "promised" it was not fixed in version 11...

Thanks
MCRider
 

lgabriel

I love flying!
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Nov 25, 2013
Messages
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I haven't lost interest in this either--it would be incredibly helpful to analyze what my right electrical system is up to.
 
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