VTI Instruments Ametek EX1200A Series, User Manual

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Appendix B 159

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)
= c
ard’s
consu (number of relays closed)(relay consumption)
I
5V (EX1200-2001)
= 0.0037 A + (6)(75 mA)
I
5V (EX1200-2001)
= 0.454 A
I
5V (EX1200-3048)
= 0.0041 A + (10)(23 mA)
I
5V (EX1200-3048)
= 0.234 A
With the switch card’s total power consumption calculated on the 5
V rail, consumption for each
rail can be calculated:
P
24V
= 24 V x [ I
24V (EX1200-3608)
+ I
24V (EX1200-2001)
+ I
24V (EX1200-3048)
]
P
24V
= 24 V x (1.4 A + 0 A + 0 A)
P
24V
= 33.6 W
P
5V
= 5 V x [ I
5V (EX1200-3608)
+ I
5V (EX1200-2001)
+ I
5V (EX1200-3048)
]
P
5V
= 5 V x (1.000 A + 0.454 A + 0.234 A)
P
5V
= 8.44 W
P
3.3V
= 3.3 V x [ I
3.3V (EX1200-3608)
+ I
3.3V (EX1200-2001)
+ I
3.3V (EX1200-3048)
] / 80% efficiency
P
3.3V
= 3.3 V x (0.300 A + 0.131 A + 0.129 A) / 80% efficiency
P
3.3V
= 2.31 W
To verify that this is a valid configuration, the values can be substituted into the criteria above:
1) P
24V
+ P
5V
+ P
3.3V
≤
120 W
→ 33.6 W +
8.44 W + 2.31 W
≤
120 W (True)
P
24V
+ P
3.3V
≤
84 W
→ 33.6 W +
2.31 W
≤
84 W (True)
P
5V
≤
75 W
→ 8.44 W ≤
75 W (True)
P
3.3V
≤
24 W
→ 2.31
W
≤
24 W (True)
The remaining power for this mainframe is 75.65 W for additional cards to draw from.