Sorry this took so long but the project manager responsible for assigning the engineer was on vacation and the engineer figured he would wait until ordered. :)
As shown in the above figure, PSE output voltage is observed to drop from 48.6V to 47.48V using 11.2ms.
dV/dt = (48.6-47.48)V/11.2ms = 1.12V/11.2ms = 100 V/s
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CASE 2: Internal Power Supply Failure with maximum load resulting in ports dropping, measure port.
As shown in this figure, PSE output voltage is observed to drop from 48.7V to 46.86V using 12.8ms
dV/dt = (48.7-46.86)V/12.8ms = 1.84V/12.8ms = 143.75 V/s
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CASE 3: Internal Power Supply Failure with sub-maximum load resulting in no ports dropping, measure port.
As can be seen in the measurement above, no change in voltage is measureable.
I should note that the probing method is not described, but this noise appears to be due to measurement. We have performed low-noise measurements on the ports and seen much better plots.
Regards,
Dan Dove