target signal to chase on time history plot

[Christian Reinecke]

Hello, 

for some specific engine test maneuvers, we would like to create a target signal for power lever position, which can be chased by use of a time-history chart on the pilot display. We are able to create the desired target signal based on using the SawtoothWave function. However, there is no option to trigger the starting point of the pattern e.g. on button/command. 

Is there any way to achieve what we are looking for by using IADS built-in functions?

Thanks

Chris

[Chant, Adam]

Christian,
Consider using a reset or Toggle button in your equation to set the running value to a known out of range value (like 0) when not in use.
Create a IADS Button Input object and set the OutputName to “PLPReset” then use GetUserInput(…) function as its own derived parameter (PowerLevelReset) to feed a conditional statement in your equation.

PowerLevelReset ? 0 : SawtoothWave(40,60,1)  [If the reset button is true then return 0 otherwise run the equation]

 

I do not recommend using GetUserInput() inside of the equation as it could have unexpected behavior when testing in a playback client.

 

Also you’ll want to make the derived parameter an IAP if you need to see the correlation of the reset events with actual data. Otherwise the reset events will get lost and you’ll just see the equation run through the duration of the data. IAPs only work in real time so you’ll have to set the Derived to Iap prior to real-time test or at the very beginning of real-time. Additionally do no change the IAP Parameter’s DataSourceARguement once it is an IAP or it will reset the parameter and lose all of the previously recorded values.
For more details on IAPs vs Derived parameters in IADS see the help.

Thank you,

Adam Chant
Project Engineer, IADS

Curtiss-Wright
190 Sierra Court A-3 Palmdale, CA 93550
T: 661.273.7003 x 2210
ach...@curtisswright.com

iads-s...@curtisswright.com

 

From: 'Christian Reinecke' via IADS <ia...@googlegroups.com>
Sent: Monday, June 8, 2026 7:31 AM
To: IADS <ia...@googlegroups.com>
Subject: [IADS] target signal to chase on time history plot [EXTERNAL]

 

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[James Bretz]

Just FYI, there's really no way to start the pattern of a SawtoothWave because its value is based on time. 

The bottom line is that you'll have to make your own sawtooth wave using an equation.

If you just a need a ramp, you can use an equation similar to:

PowerLevelReset  ->   GetUserInput( “PLPReset” )     Type=int  UpdateRate=100

Ramp ->    PowerLevelReset ? this + 0.5 : 0            Type=float  UpdateRate=100

'this + 1' one tells the equation to take the previous value of the equation and 0.5, essentially creating an infinite ramp. You can control the slope of the ramp by changing the increment. If you set the sample rate of the parameter to 100, the equation will be called 100 times in one second. Use this knowledge along with the increment value to get the desired slope based on a time range.

If you do require a SawTooth, let me know and I'll try to think of an equation. We might have to cheat with some advanced undocumented features ;)

Jim  

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