Series 3700A Switch and Control Cards Reference Manual
Section 3: Series 3700A cards power usage
3700AS-909-01 Rev. B / December 2011
3-7
Example 6
This example demonstrates how to calculate the card power of the 3750 when used only as digital
outputs.
Setup Power
Notes
3300
Static power required of card under default
conditions (that is, all functions enabled).
CH 1 through 5 set as
OUTPUT
365 * 5 = 1825
CH 6 through 9 =
disabled
-730
Static power is reduced by disabling the
totalizers (channels cannot be individually
disabled).
CH 10 = disabled
-820
Static power is reduced by disabling analog
output channel.
CH 11 = disabled
-820
Static power is reduced by disabling analog
output channel.
Total Power
2755 mW
NOTE
:
Bank power would not be
exceeded if three cards per bank
were used in this manner.
Example 7
This example demonstrates how to calculate the card power of the 3750 for digital inputs and two
analog voltage outputs.
Setup Power
Notes
3300
Static power required of card under default
conditions (that is, all functions enabled).
CH 1 through 5 set as
INPUT
0
CH 6 through 9 =
disabled
-730
Static power is reduced by disabling the totalizers
(channels cannot be individually disabled).
CH 10 = V mode
470
CH 11 = V mode
470
Total Power
3510 mW
NOTE
:
Bank power would not be exceeded if
three cards per bank were used in this
manner.
Hardware interlocks
Some switching cards are capable of switching high-voltage signals. For safety reasons, hardware
interlocks are provided. The hardware interlocks are present on the switching card itself and are
designed to keep the switching card disconnected from the system backplane. This means that when
the interlock circuit is disengaged, no measurements can be performed through a switching card.
However, channel relays can continue to operate.
Below is a simplified schematic of the interlock circuit present on the applicable switching cards.