buffer and trigger questions

[adam.polak]

Hello, sorry for finishing one topic and starting another, but I thought that it will be better to keep it separate since subject is somehow different.

I'm struggling with few questions and hope that somebody from the community will be able to help me out.

Buffer related questions:
I know that at this moment buffer size is 16k samples and it is not to be discussed. But I'm wondering:

- > why in the Matlab examples buffer size is define as

tcpipObj.InputBufferSize = 16384*32;
tcpipObj.OutputBufferSize = 16384*32;

what this ' *32' is doing? additionally in another example there is ' *64' . could somebody explain what's the reason for this definition?

- > Am I able to define smaller buffer by the commands above? I was trying some smaller buffer sizes but then it returns error that terminator is not reached and actually nothing was acquired. I'm thinking about smaller buffer because 16k is not enough for me to collect all the data I need so I was thinking to acquire smaller packages of data, quickly save it to the hard drive, and acquire next package of data in small buffer size.. is it possible?

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And now Trigger related questions

1. is it possible to use digital channels to generate 100Hz (for example) pulse signal as external trigger (I need Ch1 and Ch2 of fast analog input for acquisition of other data)?
2. I don't really understand what is the methodology of correct preparation of trigger settings for simultaneous trigger of generation and acquisition of the data. When I'm following the example I'm getting data acquired in various stages from the moment when generation was started. How should i choose the delay value (in a understandable way - right now I'm just plotting all the data with delay=0 and looking when something stars) ? For my lack of understanding it's randomly changing, depending on decimation used, trigger type and trigger level value.
3. why sometimes RP is acquiring some strange parts of signal before actual signal is being acquired after n samples? and when the actual signal is acquired then it does not start at the same place where generated signal should start but somewhere else , meaning - it's not synchronized generation and acquisition.
4. what would be the recommendation for trigger if on both fast channels I want to collect signals which by their nature cannot become trigger, but still I'd like to generate signal on fast analog outputs and acquire both inputs simultaneously? I was thinking about external trigger, but I'm aiming on using RP only therefore see again question 1

I will be grateful for any explanations.. suggestions.. help...
all the best
Adam