Detect and save an event and the previous 60s data in a R32 file

Question

Hello
I am a new user of Diadem.
I perform long reliability test, and so the R32 file reach often 1 Giga byte (with a measure frequency of 500hz) when I stop manually the measure after the event . And after I only use the last 60s.
I acquire a Voltage signal using a measurement instument connected to the Serial port, I save this signal in a document by using the document icon in the DAC (Circuit with packaged data)
I have read the manuals but I don't know how to do the following thing:
How to save only the last 60s in a buffer and write it into a file if they are followed by an event.
The signal has normaly each 10s a 10v spike (During 7ms) but some time it remain constant near 4V during at least 5s and that is the event.
How to do that in the DAC? Should I use a trigger with a timer condition, but I don't know how to do it with packaged data.
Could you give me an example
Thanks for your help
Alfons

Answer 1

Hello,
I have
created two Examples how to do this.
The basic idea is to build packets with 60 seconds of data, find the event and
save the last minute. One way to create the packet with 60 Seconds is the
Offset Register. This block is also able to shift the signal by smaller steps.
The signal
is created with two generators and a manual switch to create the stop event. The
blocks are running free, so you don’t have to wait a minute or more to test the
behaviour. It is possible to simulate real timing in the generators if you like
to see the real speed.
In the
simple example the Offset Register “1 Minute” is producing a packet with the
last 30.000 values 10 times per second. This is shown in a scope. After this, a
formula is looking for values between 2 and 6. All values in the packet are
counted and if the number is above 2.500 (5 seconds) the block Relay gives
this packet into the store and stop block. (Store is simulated with a scope to
make testing easier.
This
example should do the job.
I have also
included an advanced example.
In this
example a formula is creating a second signal with trigger information. This
signal has the same amount of values and can be used for more complex ways of
triggering. In this example the formula is measuring the time when the signal
is between 2 and 6. When the signal is not in this range the time is set to zero.
The Multiplexer Block is used to build a loop to put the result of the formula
back in to the formula. This allows the formula to ad 0.1 seconds to its own result
from the loop before.
The trigger
signal is later used to store and stop the test. It is possible to create very
flexible triggers, events and decisions during a process if this is needed.
Of course,
it is possible, that you have to change some of the blocks or add additional functions
if the simple formulas are not able to separate the event from other changes in
the signal.Ulrich Bierwisch
Attachments:
simple.DAC ‏37 KB
advanced.DAC ‏46 KB