User manual

905K Radio Telemetry Module User Manual
 ELPRO Technologies Pty Ltd 2010 Page 20
Voltage Supply
∆ volts (6 – 30)
BU-5 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 / ∆
0.040 x w-time
per measurement.
Current = (355/9)mA
while warming up and
sampling.
Loop Powered Transducer - 20 mA average
576 / ∆
0.064 x w-time
per measurement.
Current = (576/9)mA
while warming up and
sampling.
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 BU-5 battery pack is used, these figures can be used to determine the expected battery
life. A BU-5 with new batteries has a capacity of 1.7 amphours (1700 mAHr). If two BU-5’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 BU-5 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:
Digital input Update time, off state 1 day Update time, on state 15 minutes
Input is expected to be on twice per year for 4 hours
No. of change messages per year = 2 (twice per year) * 2 (on to off and off to on)
= 4
No. of “off” update messages per year = 364 (approximately)