Drew Technologies DASHDAQ-XL User Manual
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Rescale Signal Calculator
Allows you to adjust a single signal or use multiple signals to create a custom signal for you to monitor and log. This provides the
ultimate in flexibility because you can multiply two signals together, add/subtract two signals, multiply a signal by a constant value, etc.
The Rescale Calculator use a simple linear equation, Y= M * X + B, to configure custom user signals:
Output Signal = Input Signal * (Multiplier Signal or Constant Multiplier) + Offset Signal
Install the Rescale Signal Calculator following the steps found in the “installing a Calculator Driver” above.
This calculator can be installed several times; once for each signal that you wish to rescale. There required inputs are:
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Input Signal: Signal to modify. Pick a signal for speed, voltage, or any signal you want to rescale.
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Multiplier Signal: Either a vehicle signal, or “Constant Multiplier” described below.
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Multiplier Sign: Specify 1 to leave the multiplier unchanged, or -1 to make the multiplier negative.
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Constant Multiplier: Can be a positive or negative whole number or decimal and will be multiplied to the Input Signal. Leave
as 1 if no multiplier is needed.
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Offset Signal: Either a vehicle signal or “Constant Offset” described below.
•
Offset Sign: Specify 1 to leave the offset unchanged (add), or -1 to make the offset negative (subtract).
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Constant Offset: Can be a positive or negative whole number or decimal and will be added to the Input Signal. Leave blank if
no Constant Offset is needed.
Additional Inputs:
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Name: Abbreviation to identify this signal. Used as a gauge label and displayed on the assign signals screen.
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Units: Physical units for the calculation. Any automatic Imperial/Metric occurs afterward. For example, if a calculation results in
°C the number could be automatically converted to °F before display.
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Precision: Number of decimal digits to display. The more decimal places shown will cause the signal to change more often.
The calculated values will be available under “Rescale Signal Calculator” when you assign signals to a gauge.
EXAMPLE: CALCULATING BOOST
Many vehicles do not provide an enhanced signal for Turbo Boost but it’s pretty easy to calculate. Boost is achieved when MAP
pressure is greater than Barometric pressure.
This calculation looks like:
BOOST = MAP - BARO
To perform this calculation on the DashDAQ, try setting:
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Input Signal: Manifold Absolute Pressure from GenericOBD II or other MAP signal input
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Multiplier Signal: Constant Multiplier from Rescale Signal Calculator. Use [<] or [>] at the top to locate.
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Multiplier Sign: 1 (Positive).
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Constant Multiplier: 1.0.
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Offset Signal: Barometric Pressure from GenericOBD II or other BARO signal input. If no Barometric pressure signal available
select Constant offset.
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Offset Sign: -1 (Subtract)
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Constant Offset: The current or average Baro pressure value for your region. (US avg. ~14.7)
•
Name: Boost