ethercat speeds and sample rates
For many years now I have been running long coax cables from distrubuted sensors to a central recording maching (once a dewe-5000 now a pair of synched dewe-43s).
The environment is quite noisy and it would be better, I'm sure (expense aside), to use ethercat enabled devices close to each set of sensors then connect them to a central storage PC.
However, our total sample rates are high, 8 or 16 channels running at 24kS/s and sometimes up to 200kS/s (we also need very good sync between channels).
What total sample rate can be supported by the ethercat data transfer?
(the spec sheet says 100Mbits/s = 1.5MB/s? which looks like plenty for 8x 50kS/s channels .... however when I discussed this at the last dewesoft conference, I'm sure we concluded that it wouldn't work ... but now I can't think WHY it wouldn't work).
the problem is that EtherCAT can only do 160 kS/sec. In the case of DEWESoft's EtherCAT line, that means 20 kS/s per channel for regular EtherCAT devices (SiriusE, Krypton STG/LV) and 10 kS/s for HD SiriusE slices. If that's fast enough for you, then you can chain multiple units together and only have one cable leading back to your PC terminal.
If you want higher speeds and the distance is not to great, meaning you connect USB cables from your measurement site to the PC, then you can use the speed boost feature of our SiriusE devices. You basically still use the EtheCAT cables fro power and sync, but the majority of the data transfer will be done through the USB. That way you can achieve 200 kS/s.