HP 8-Channel 196 kSa/sec Digitizer plus DSP E1433A manual Limit on Queuing of Data

HP E1433A User's Guide

Using the HP E1433A

Limit on Queuing of Data

In overlap block mode, a number of trigger events may be queued up before the host reads the data for those triggers. The host may get further and further behind the data acquisition.

However, if the host gets far enough behind that the FIFO fills up, data acquisition must momentarily stop and wait for data to get transferred to the host. This places a limit on how far in time the host can be behind the data acquisition. By setting the size of the FIFO, is you can control how far behind the host can get.

Making Overlap Block Mode Act Like Traditional Block Mode

If the FIFO size is set the same as the block size, or if the number of pending triggers is limited to zero, then overlap block mode becomes identical to traditional block mode.

Making Overlap Block Act Like Continuous Mode

If the module is in auto-arm and auto-trigger mode, then overlap block mode becomes nearly the same as continuous mode.

One difference is that traditional continuous mode has a single arm and trigger, while overlap block mode may have multiple arms and triggers. Another is that continuous mode can be configured to start at any type of trigger event, while overlap block mode must be in auto-trigger mode to act like continuous mode. Finally, continuous mode always stops when a FIFO overflow occurs, but overlap block mode does not.

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