Question: What is the maximal readout data rate and bandwidth the iGp12 unit can support?

Internal bus from the IOC to the hardware supports roughly 43 MB/s transfer rate. Normally, this high data rate is not exposed to the outside world, with IOC post-processing reducing the 2-D data matrix to a set of vectors (mean, RMS, max RMS record, spectrum).

With Gigabit Ethernet one can actually stream the data out at nearly the full rate. At BESSY II with 18 ms acquisition time (corresponding to 17.2 MB data block) Andreas Schälicke has achieved roughly 34.5 MB/s average network utilization with 2 Hz readout, peaking at 66 MB/s Ethernet usage (theoretical maximum for Gigabit Ethernet is 125 MB/s).

Update: As of IOC revision 2.8 and FPGA gateware 3.11, 2 Hz acquisition rate is supported for full SRAM size, 12 Msamples. External streaming is limited to slightly shorter blocks of 11.4 Msamples.

— Dmitry Teytelman 2013/05/23 10:51