Block size issue

[Benedikt]

I'm using DASYlab to acquire data from a cyclic test using an USB-2537 DAQ card. I have an issue when trying to acquire at higher sampling rates. When using a high sampling rate (10 kHz) with a small block size (10), the data is not treated by the computer, the update of the digital instruments, graphs etc. gets extremely slow, finally resulting in a overflow in the DAQ module.

When I increase the block size (1000) everything runs smooth, BUT a bock contains always identical values, resulting in a stair case and decreased resolution depending on the frequency of the signal.

What is wrong? It is very urgent, since I have a project deadline on Monday. Thanks for you help!

[DAQman]

The recommended block size is 10% * Scan Rate. It must be big enough to prevent the internal buffer from backing up. Every module in your worksheet gets time to run. It cycles through them all and returns to the analog input to get more data. If you have a large worksheet, it will take more time to process, which requires a larger block size.

I'm sorry, I don't understand what you mean by the block containing identical values when it's bigger. Please provide an example of data and what is connected to the input. If your worksheet is not too crazy, attach it, and I try to load it here.