Fuel Totalizing Computation


fa_total <priority> <interval> <filename> [+c]



Specify the system task priority.


Specify the process interval. Specify one of FAS, MED, or SLO. The interval value is in milliseconds.


Specify the path of the specification filename.


Optional. Specify this flag to indicate a critical task to the watchdog.


fa_total 8 1000 /specs/fa_specs.315 +c &
The above command spawns ‘fa_total’ in the background at a priority of 8.
The computations are performed once every second using the specifications
in the file /specs/fa_specs.315. The task is also assigned to be a critical
task. As a result, if the task ever stops responding to the watchdog, any
test that is running will be aborted.  The fa_total task will register its
name with the filename (not the full pathame), in this case
“fa_specs.315”.  This name can be used by the ‘re-read’ command to request
that it updates the specifications by reading the specification file again. 
This feature allows the specifications to be changed “on-the-fly” without
slaying and restarting the app. Note: re-read feature is not available
prior to 6.3.30 or 6.4.0.


This task is normally started in the go script that starts CyFlex.

fa_total is not a mass flow measurement application such as “lc_scales”,
“cf_scales”, or “scales”. The primary purpose of fa_total is to
continuously sum one or more fuel flow values with one or more air flow
values and calculate the following:
Total fuel rate (Fuel_rate)
Air-fuel equivalence ratio (lambda)
Total dry mass air flow rate (air_mtr0_mfd)
Total wet mass air flow rate (air_mtr0_mf)
Fuel-air equivalence ratio (phi)
Air-fuel ratio (AF_ratio)

All of the above variables are specified in perf_labels and will be updated
by fa_total at the rate specified when it is spawned. You cannot configure
which variables fa_total updates, it will always update the variables created
by perf_labels.

In order to calculate these values, the following variables are needed as inputs
to the program:
Power generated (Dyno_power)
Fuel mass flow variable(s)
Dry air mass flow variable(s)
Wet air mass flow variable(s)

The variable used for Dyno_power is specified in perf_labels. The fuel and air
mass flow variables are specified in the fa_specs spec file.

fa_total will also update the following variables during a fuel reading. These
variables are created by sys_start and specified in /cell/logi_specs:

The most common use for fa_total is when using a continuous fuel flow measurement
device such as a Flotron, Coriolis meter, or a positive displacement meter of some kind.

Use fa_total for a continuous fuel flow measurement device such as a Flotron or Coriolis meter, or a positive displacement meter of some kind.

See Also:

Fuel Air Total Computation, re-read