Pressure curve sampling

[Chorlton1]

I need to sample a pressure curve from a flame passing down a pipe the signal is 0 - 10V scaled to represent the pressure sampled by a Iotech DAQ3000.

The standard I am working to states the following

"The average value of the detonation pressure shall be calculated from the area integral below the pressure-time trace, starting at maximum pressure peak and covering a time interval of 200 µs."

I need to trigger the sample at the maximum pressure peak then continue for 200 µs and make the calculation stated.

[CJ_Butler__DASYLab_Pro]

Try the Min/Max module, configured for TTL pulse, and then use the TTL as the input to a Combi Trigger, configured for the post trigger settings that you need.

Use the output of the Trigger to control a relay where the input is the pressure signal, and you'll get a snapshot of the signal where you can then run the Integration.

[Chorlton1]

I am using Dasylab V9 and there doesn't seem to be a TTL Pulse only output modes are Function Value and TTL Peak. Using TTL Peak just gives me a list of 0 or 5 could you give me a worked example showing the settings for each module?

[CJ_Butler__DASYLab_Pro]

Look under Statistics for the Min/Max module.

[Chorlton1]

I found the min/max module but there isn't a TTL pulse option only TTL Peak

[CJ_Butler__DASYLab_Pro]

That's the setting. I don't have V9 available, and I picked that out of my failing memory. Sorry.

The output of Min/Max is either a value or a 0/5 signal, where it outputs 5 at the time of the peak, and 0 for the rest of the signal.

[CJ_Butler__DASYLab_Pro]

Here's my V11 worksheet

and the module settings. Note that for a high data rate, I had to turn off the "Limit data flow (FIFO size)" settings, making it possible that DASYLab will consume lots and lots of memory.I'm not sure whether V9 had this feature or always limits.

[Chorlton1]

I am getting an error message Relay03 mismatched input channels.

[CJ_Butler__DASYLab_Pro]

How did you configure the Min/Max? It should be the TTL mode, not the value mode.

[Chorlton1]

Apologies after some tweeking of the settings that were not detailed I think your solution will probably work for me.