Illegal blocksize FFT-Module

[AM-Locha]

Good Morning,

I'm using DASYLab V11.0.1 on a WIN XP SP3. I want to use the following Worksheet for a long-time-measurement. (Here you see no Inputs, it's a simulation)

For reducing the measurement data, the aquisition shell be controlled by events.

If the Inputs (Signal_offen AND Signal_zu) have a Low-TTL, the data should be recorded.

Othervise the data shell be recorded every hour for 6 sec (controlled by the Module Impulsgebe00).

The Worksheet works so far, but if I want to analyse the first three inputs with a FFT-Module, I get the message "Illegal block size.Stop." when the "Relais" close.

(Low-TTL at the control input of the relais; see "Trigger-Anze")

I hope you can help me. Or maybe someone have an other solution.

[MHa]

AM-Locha,

is it possible that you can append the simulation dsb into forum thread. Thanks.

Best regards,

MHa

[AM-Locha]

Sure

[MHa]

Thanks. I would like check now the situation and contact you later ...

Best regards,

MHa

[AM-Locha]

It seems to work with an Generator and a Action-Module like in the dsb-file, which I've posted.

[MHa]

I have checked the DSB from appendix - a little bit other as screen shot - but general same "kernel" problem.

(1) Your DSB have a Experiment setup blocksize from xxx, for instance 32768.

(2) The FFT module set this blocksize value xxx with start from DSB for an internal reference value xxx.

(3) Every incomming block for the FFT module is checked in relation to this reference value xxx.
(4) The Relais module into the data flow reduce the incomming values for FFT for < xxx.
(5) The FFT check routine detect this problem and generate the Error Message what you see.

What is to do:

- DASYLab 11.0.1 - the combination Relais and FFT is not possible
- I check the situation / possible workarounds? and contact you later ...

Best regards,

MHa

[AM-Locha]

Thank you so far!

I've insert a Generator (with a constant Offset) in the position of the Impulsgenerator. I've connected the impulsgenerator to a Action-Module, which modulates the Offset of the Generator (High -> 5V; Low -> 0V)

And it's seems to work.

But I don't understand why it doesn't work with the Impulsgenerator directly 😞

[AM-Locha]

Ok, I think I have the solution 🙂

How you allready explained, the Impulsgenerator "cuts" the Block to a smaller size, so the FFT-Module generates a Error Message.

Due to connecting an Action-Module and a Generator, like I've written above, the Generator don't switch to 0V till the Block is "full".

You can see it in the following Diagram.

Blue = Impulsgenerator; Red = Generator

MHa, what do you think about my thoughts? Is it plausible?

 

[MHa · Accepted solution]

If you solve (4) incomming value block = xxx with this change then you can use the module data flow with Relais and FFT.

[AM-Locha]

ok, thank you very much for your support!

Greets AM-Locha