fodrv7
Well Known Member
GRT AUXSF & AUXOFF explanation
Below is an explanation of AUXSF and AUXOFF for those who want to do more than blindly follow the GRT instructions.
The brief is available as an MS WORD doco (Which is easier to read) by request to [email protected]
AUXSF & AUXOFF Logic.
? AUXSF Scales the indication so that a change in a condition is correctly displayed. For example, you burn 20 litres of fuel and the gauge goes down 20 litres.
? However, it might go down from 220 litres to 200 litres? when you know full tanks is only 80litres.
? AUXOFF is a means of Offsetting the scale so that zero is indicated for zero value. Fuel, Amps or whatever.
You MUST adjust AUXSF FIRST.
An example, adjusting AUXSF & AUXOFF for AMPS.
? To make it simpler the numbers I have shown are not what I had, but chosen to make the logic easier to follow
? The Readings Amps Min was with only the Master on.
? The Readings Amps Max was with everything on.
? In this case I used an old fashion ammeter to read the actual current.
? GRT Told me to start with AUXSF/OFF of 100/177 which I did.
AUXSF set to 100 Amps Min Amp MaX Change
Actual Measured 5 21 16
GRT reading 16 48 32
? From the above you can see that the GRT is sensing a change in AMPS of 32 when the actual change is 16.
? Therefore the GRT is twice as sensitive as it needs to be and AUXSF should be adjusted to 50% of it?s current value. Ie AUXSF 50.
AUXSF set to 50 Amps Min Amp Max Change
Actual Measured 5 21 16
GRT reading 8 24 16
We would now see the correct increase in AMPS if, for example, we turned on the Landing light, but the GRT is over-reading by 3AMPS across the whole range.
Therefore we need to input an OFFSET to reduce the reading by 3AMPS.
That?s the logic, however;
? The Offset needs to be scaled by the same amount as the AUXSF.
? Sometimes it must be an ODD number.
Pete.
Below is an explanation of AUXSF and AUXOFF for those who want to do more than blindly follow the GRT instructions.
The brief is available as an MS WORD doco (Which is easier to read) by request to [email protected]
AUXSF & AUXOFF Logic.
? AUXSF Scales the indication so that a change in a condition is correctly displayed. For example, you burn 20 litres of fuel and the gauge goes down 20 litres.
? However, it might go down from 220 litres to 200 litres? when you know full tanks is only 80litres.
? AUXOFF is a means of Offsetting the scale so that zero is indicated for zero value. Fuel, Amps or whatever.
You MUST adjust AUXSF FIRST.
An example, adjusting AUXSF & AUXOFF for AMPS.
? To make it simpler the numbers I have shown are not what I had, but chosen to make the logic easier to follow
? The Readings Amps Min was with only the Master on.
? The Readings Amps Max was with everything on.
? In this case I used an old fashion ammeter to read the actual current.
? GRT Told me to start with AUXSF/OFF of 100/177 which I did.
AUXSF set to 100 Amps Min Amp MaX Change
Actual Measured 5 21 16
GRT reading 16 48 32
? From the above you can see that the GRT is sensing a change in AMPS of 32 when the actual change is 16.
? Therefore the GRT is twice as sensitive as it needs to be and AUXSF should be adjusted to 50% of it?s current value. Ie AUXSF 50.
AUXSF set to 50 Amps Min Amp Max Change
Actual Measured 5 21 16
GRT reading 8 24 16
We would now see the correct increase in AMPS if, for example, we turned on the Landing light, but the GRT is over-reading by 3AMPS across the whole range.
Therefore we need to input an OFFSET to reduce the reading by 3AMPS.
That?s the logic, however;
? The Offset needs to be scaled by the same amount as the AUXSF.
? Sometimes it must be an ODD number.
Pete.
Last edited:
