HLIS display vs. dataref value

[Rodeo]

Using version 1.4r1, macOS Catalina, X-Plane 11.55

I have code to print the HLIS dataref's contents after touchdown when passing 25 knots GS and decelerating:

            if (onground_any > 0)
            {
                if (25.0f > (XPLMGetDataf(flightmodel_groundspeed) * 3.6f / 1.852f))
                {
                    if (delta_acc) // XPLMFindDataRef("CL650/HLIS/delta_acc")
                    {
                        log("[info]: landing (detected): CL60 HLIS acc %.3f\n", XPLMGetDataf(delta_acc));
                    }
                }
            }

Resulting in:

[info]: landing (detected): CL60 HLIS acc 6.104

Compared to (HLIS button pressed for two seconds later on, i.e. soon after engine shutdown, checked on the display and crosschecked with the CSV log):

HLIS % grep DeltaG HLIS-1.csv
DeltaG,0.622
HLIS %

The difference (6.x vs. 0.6x) seems significant.

Questions:

• am I printing the wrong dataref?
• is it not a float (seems unlikely)?
• do I have to process delta_acc get to DeltaG somewhow?
• do I really have to print the dataref even later than I do now?
• is there a different issue I'm not aware of?

Regards,

Tim

HLIS-1.csv.zip HLIS.nvram.zip

Edited March 22, 2022 by Rodeo

[Pils]

Here is what Toto said:

The datarefs are named:
``CL650/HLIS/delta_acc`` - the recorded peak delta-acceleration in m/s/s
``CL650/HLIS/norm_acc_log[0..120]`` - a running log of the normal acceleration (in m/s/s) received by the HLIS from the IRSes. Entry [0] is the latest data and progressing backwards in time at 40 samples per second. This gets continuously overwritten in flight and stops being updated 3 seconds after landing (at which point the HLIS computes the peak delta-G value).

Edited March 22, 2022 by Pils

[Rodeo]

Right, so I need to compute the peak delta-G somehow myself then, correct?

Regards,

Tim

[Pils]

10 minutes ago, Rodeo said:

Right, so I need to compute the peak delta-G somehow myself then, correct?

Regards,

Tim

Yes. “Somehow” is a simple division. ¯\_(ツ)_/¯ 

Edited March 22, 2022 by Pils

[Rodeo]

Good point. It's past my bedtime though, AP ON BRAIN OFF