Ex12X8 Power Consumption Calculation - VTI Instruments Metek EX1202 User Manual

For example, an EX1266 is populated with the following three cards:

EX1200-2001 with six (6) relays closed

EX1200-3048 with ten (10) relays closed

EX1200-3608
From the Plug-in Module Power Consumption section, the amount of current used by the switch
card's relays can be calculated and added to the total consumption on the 5 V rail:
I
5V (EX1200-2001)
I
5V (EX1200-2001)
I
5V (EX1200-2001)
I
5V (EX1200-3048)
I
5V (EX1200-3048)
With the switch card's total power consumption calculated on the 5 V rail, consumption for each
rail can be calculated:
P = 24 V x [I
24V
P = 24 V x (1.4 A + 0 A + 0 A)
24V
P = 33.6 W
24V
P = 5 V x [I
5V
P = 5 V x (1.000 A + 0.454 A + 0.234 A)
5V
P = 8.44 W
5V
P = 3.3 V x [I
3.3V
P = 3.3 V x (0.300 A + 0.131 A + 0.129 A) / 80% efficiency
3.3V
P = 2.31 W
3.3V
To verify that this is a valid configuration, the values can be substituted into the criteria above:
1) P
24V
2) P
24V
3) P
5V
4) P
3.3V
The remaining power for this mainframe is 75.65 W for additional cards to draw from.
EX12 8 P C
X OWER ONSUMPTION
EX12x8 mainframes are powered by four power supplies. Although these are the same power
supplies as used in the EX12x2 and EX12x6 mainframes, one power supply is solely responsible
for supplying the 3.3 V power while the remaining three supplies provides power to specific slots,
or segments, of the backplane. The three segments use the following slots: 1 through 5, 6 through
10, and 11 through 16 (see Figure B-1). While the 5 V and 24 V rails are divided into segments,
the single power supply that provides the 3.3 V rail does so for all sixteen (16) slots.
Appendix B
= card's consumption + (number of relays closed)(relay consumption)
= 0.0037 A + (6)(75 mA)
= 0.454 A
= 0.0041 A + (10)(23 mA)
= 0.234 A
+ I
24V (EX1200-3608) 24V (EX1200-2001)
+ I
5V (EX1200-3608) 5V (EX1200-2001)
+ I
3.3V (EX1200-3608) 3.3V (EX1200-2001)
≤ 120 W
+ P + P
5V 3.3V
≤ 84 W → 33.6 W + 2.31 W ≤ 84 W
+ P
3.3V
≤ 75 W → 8.44 W ≤ 75 W
≤ 24 W → 2.31 W ≤ 24 W
C
ALCULATION
+ I
24V (EX1200-3048)
+ I ]
5V (EX1200-3048)
+ I
3.3V (EX1200-3048)
→ 33.6 W + 8.44 W + 2.31 W ≤ 120 W
(True)
(True)
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]
] / 80% efficiency
(True)
(True)
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