can't seem to obtain data in a specific measurment window

[KCL64]

Looking for a way to have a dasylab look only at data within a specific 25 milesecond window .

This is a repetitive event that happens  100 times per minute but data I want is only valid within a 15 degree window (25 ms)

I have a digital input that is timed for the 15 degree window signalling a relay within dasylab ,but the data that dasylab is gathering is sometimes outside this window and therfore not accurate. Not sure if it's a program or hardware issue at present.

Using an MC USB-1208FS DAQ

Anyone have any suggestions on this ?  Thanks Kent.

[CJ_Butler__DASYLab_Pro]

You want to look at a 25 millisecond window, but your timebase is 10 samples/second One sample every 100 ms.

You need to sample at a much higher rate. How many samples do you want to see in the 25 ms window? 

I believe that you are undersampling, and therefore missing your data.

[KCL64]

3 samples within the 25 ms would be great as a minmum. I need to learn more about the dasylab time bases.  Thanks Kent.

[KCL64]

If I try and increase my measurement rate I get this error.

[JeffAtMcc]

I recommend you not use the digital input to acquire that data.  Instead, use 3 analog inputs, set the timing for Hardware, at a much higher rate and send the data that was for the digital input now coming off the analog input to the relay's control.

[KCL64]

Hi Jeff Anyway you can demenstarte what you mean. I'm finding that dasylab programming is somewhat over my head . Thanks Kent.

[JeffAtMcc]

I thought I had attached this (sorry), but here it is, the modified version of your worksheet with the changes I suggested.

[CJ_Butler__DASYLab_Pro]

What Jeff forgot to say... the digital subsystem on this device is relatively slow, and can only be clocked with the software (computer paced) timing. That's limited. The analog input subsystem has a hardware (device based) clock that allows higher sample rates.

To get around the slow DIO subsystem, connect the wire that is connected to the Digital input pin on the USB-1208FS to an analog channel pin, and acquire it as an analog signal.

Once acquired, the data is just numbers for DASYLab, and the Relay will interpret an analog value as a TTL Low or High, depending on its amplitude.

[KCL64]

Ok I'm following you so far. I get this error message when I try and run program. as I still have a digital output to deal with.

[KCL64]

Any free lancers out there that are willing to write some dasylab code to help me with this application.? Thanks Kent