Sifos Technologies PowerSync PSA100, Technical Reference Manual, Page: 54 / 147

PowerSync Analyzer Reference Manual
March 9, 2010 Sifos Technologies page 54
3.4.5. Measuring Inrush Current during Class 3 Power-Up with ALT A, MDI PSE on Port 1,1
This procedure will yield the maximum inrush current (or current limit applied) during a Class 3 emulated power-up
sequence. The peak current meter will be used to return this value. The Class 3 emulation is performed just for
demonstration – in reality, the classification level probably won’t affect in-rush current limiting. Load current will be
sampled from PoE voltage crossing through 35 VDC for the next 20 mSec. A 10 mSec transient at 500 mA will be
generated on the same power-up trigger event.
Menu Task Picture
Configure the port for the PSE type
Select Slot 1 and Port 1
Select ALT A
Select MDI
Select Resistance = 23 K
Ω
Select Capacitance = 0.14 µF
Apply Settings
DONE
Port
Configuration
Configure classification emulation and a
maximum surge current and retain configuration
Select Class 3
Apply PD Emul.
Change Step 1 Current Setting to 500 mA
Change Step 1 Duration to 10 mSec
Initiate Transient
DONE
Note : The Config Trigger will set the Trigger 1 criteria to
Rising at 35VDC. This is a good setting for this
measurement.
Load
Configuration
DC Meters Configure the meter for peak current
Select DC Current
Select Max Peak
Select Waveform Trigger
Set Measurement Period = 20 mSec
Apply Settings
Ensure power-down and arm classification
Event Controls
Power Down
Launch the measurement and the current
transient
MEASURE ( Note : This ARM’s the trigger)
Start Transient
Connect
Port
MEASURE