6 calculating power consumption – Weidmuller WI-I/O 9-K: Wireless I/O Transmitter v1.9 User Manual

Page 20

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WI-I/O 9-K

v1.9


Page 20

20+km in Australia/NZ (1W RF power permitted). To achieve these distance, at least one site

needs to be elevated on a hill or transmission tower - refer section 3.2 for more information).

2.6 Calculating Power Consumption

The following information

may be used for calculating power consumption.

Voltage Supply

∆ volts (6 – 30)

WI-BP-I/O-9-K

Battery Pack

mA

mAHr

Quiescent

constant regardless of voltage

0.14

3.4 per day

Each radio

transmission

Transmission time 42msec 6V

12V

24V

30V

700

300

180

150

0.005

per transmission

Analog input

measurement

Externally powered transducer - constant

regardless of voltage

10

Not applicable

(per measurement)

Loop Powered Transducer - 12 mA average

355 /

0.012 x w-time

per measurement

Loop Powered Transducer - 20 mA average

576 /

0.020 x w-time

per measurement

Pulse Input

0 - 10 Hz (Slow Pulse Inputs)

0.0025 x f

0.06 x f per day

> 10Hz (Fast Pulsed Inputs)

0.2

4.8 per day

w-time = warm up time in seconds

f = average pulse frequency in Hz

∆ = supply volts

The overall current or energy requirements may be calculated by using the above figures.

Total energy per day = Quiescent

+

Pulse input (if used)

+

Analog input per measurement x number of measurements per day

+

Radio transmission x number of radio transmissions per day

There is no additional power required for digital inputs.

Where the WI-BP-I/O-9-K battery pack is used, these figures can be used to determine the

expected battery life. A WI-BP-I/O-9-K with new batteries has a capacity of 1.7 amphours (1700

mAHr). If two WI-BP-I/O-9-K’s are connected, the second pack provides an additional 1200

mAHr.

Example:-

An application has one digital input, one pulse input and one analog input. It is powered by a single WI-BP-I/O-9-K

battery pack. Each radio message is configured to transmit two times.

The total power consumed = power for transmissions + power for analog loop supply + pulse input + quiescent

Power for radio transmissions:-

The configuration parameters, and estimated activity data, for each input are:

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