Series 3700 Module Schematics And Connections; Power Budgeting And Calculation - Keithley 3720 User Manual

Section 9: Series 3700 Module Schematics and Connections

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. Non-latching types of relays consume power in a sustained
fashion 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 consumes an amount of system
power in order to operate. This sustained (and roughly constant) power draw is known as
quiescent power. Quiescent power directly takes away from the power 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 3700 plug-in cards. The quiescent power is also shown. For latching type relays an "NA"
is shown.
Model
3720
3721
3722
3723
3730
3740
9-2
Quiescent Channel Relay Power
Power Consumption
(Milliwatts) (Milliwatts) Each
975 NA
1350 NA
475 NA
700 100 (2 Pole)
50 (1 Pole)
780 NA
1000 NA (Independent)
200 (High Current)
Series 3700 System Switch/Multimeter User's Manual
Backplane Relay Power
Consumption
(Milliwatts) Each
100
100
100
100
100
100
100
100
Document Number: 3700S-900-01 Rev. A / August 2007