EFLOW EF-Series - 1.7 POWER CONSUMPTION CALCULATION

EF-Series Instruction Manual
Rev 2/01 1-15
1.7 POWER CONSUMPTION CALCULATION
System power consumption determines solar panel and battery sizing for solar power. Table 1-1
provides information to assist in determining power requirements. The EF-Series Unit has low power
consumption due to a typical duty cycle of 10 to 20% for its microprocessor; the other 80 to 90% of the
time the microprocessor is shut off, with external wake-up signals reactivating it.
The Power Consumption Calculation section includes:
♦ Determining I/O Channel Power Consumption
♦ Determining Auxiliary Power Consumption
♦ Totaling Power Requirements
♦ Solar-Powered Installations
♦ Batteries
1.7.1 Determining I/O Channel Power Consumption
In estimating total I/O power requirements, the “duty cycle” of the built-in discrete output (DO)
channel must be estimated. For example, if the DO is active for an average of 15 seconds out of every
60 seconds, the duty cycle is:
Duty Cycle = Active time/(Active time + Inactive time) = 15 sec/60 sec = 0.25
Table 1-1. Power Consumption of the EF-Series Unit and Powered Devices
Device Power Consumption
(mW) in 12V System
Quantity Duty Cycle Subtotal
(mW)
P
min
P
max
Main Electronics Board; includes
base DO power consumption, RTD,
and Flow Sensor.
190 400 1 N/A
Built-in Discrete Output (load
dependent with a maximum of 300
milliamps at 12 volts). See Section
1.7.1.
0 3600 1
Serial Communications Card 30 N/A
Dial-up Modem Comm Card 250 N/A
Aux. Devices from Section 1.7.2 N/A N/A N/A
Total