pre and post trigger using analogue signal level to start trigger

[signal1]

When an open accelerometer channel reaches certain level (say 4 mV) I need a trigger to start data acquisiton, saving the previous 1.5 seconds of data across all eight channels and then stop recording and store the data six seconds after the trigger was started. 

Can DASYLab do this? 

Your help's appreciated,

Bob

vibration testing

[CJ_Butler__DASYLab_Pro]

Yes... there are two Trigger modules, the Pre/Post Trigger and the Combi Trigger that allow you to trigger on value, with defined pre and post trigger samples.

-cj

[signal1]

Hi, CJ, and thanks for the reply.

The Pre/Post trigger looks like it outputs a TTL signal after triggering. 

I need to use the analogue data from that channel so it looks like the Combi trigger is appropriate. 

How to write/save just the data acquired while triggered?  And to sort out/ discard the rest? 

Thanks,

Bob

[CJ_Butler__DASYLab_Pro]

The trigger modules are all control modules; they all output a TTL type signal, 0 or 5, that can be used by other modules.

In this case, the simple trigger configuration should look like this.

A/D  ----------- Trigger ---------------- X Relay   ----------------   Write Module
              \---------------------------------0

The trigger controls the open and close of the Relay, which release the Analog data that you branched to the second input of the Relay.

--cj

[signal1]

Sorry, but the Combi module won't work either.

It switches the output to TTL and I need to use that channel for data. 

How to trigger on a channel and keep the information?

Thanks,

Bob

[signal1]

Just got your parallel approach, will give it a try.

Thanks,

Bob

[CJ_Butler__DASYLab_Pro]

Bob,

Much as I hate to say this... please look at the tutorial in the Online Help.
The Worksheet Examples section has some specific examples for various ways to use the Pre/Post Trigger and the Combi Trigger.
You can look at those examples directly in DASYLab if you click on the link in the Help.

-cj

[signal1]

Thanks, CJ, for your help.

I belive I've got that one working.

Respects,

Bob