Section 3: Series 3700A cards power usage
Series 3700A Switch and Control Cards Reference Manual
3-2
3700AS-909-01 Rev. B / December 2011
Power budgeting and calculation
Individual relay power consumption generally depends on the type of relay. Latching-type relays
consume power only briefly in order to open or close. These types of relays are not of concern for
power budgeting purposes. Nonlatching types of relays continuously consume power in order to
maintain their state. These types of relays must be considered for power budgeting purposes.
Another power consideration is the fact that each plug-in card uses system power in order to operate.
This continuous power draw is known as quiescent power. Quiescent power directly takes away from
the power that is available to operate relays. So it must also be taken into account when budgeting for
power consumption.
The following table shows the power consumption of channel and backplane relays for various Series
3700A plug-in cards. The quiescent power is also shown. For latching-type relays NA is used.
Model
Quiescent power (milliwatts)
Channel relay power
consumption (milliwatts) each
Backplane relay power
consumption (milliwatts)
each
3720 975
NA
100
3721 1350
NA
100
3722 475
NA
100
3723 700
100
(2-Pole)
100
50 (1-Pole)
100
3724 1150
20
100
3730 780
NA
100
3731 780
67
100
3732 780
17
100
3740 1000
NA
(independent)
100
200 (high current)
100
3750 3300
NOTE
: The 3300 is reduced when
power is disabled to each analog
output channel (820 each) or
disabled to the totalizers (730 for all
4; cannot be individually disabled)
See
(on page 3-6),
(on page 3-7), and
(on page 3-7).
0 each (digital input channel)
365 each (digital output channel)
470 each (analog output)
0 each (totalizers)