Westermo RM-505U-K - Manual (Page 17)

man_505U-K_1.4.doc Dec 2008
    ELPRO Technologies Pty Ltd 2008 Page 17
= 32
Total messages for digital input = 4 + 364 + 32 = 400
Pulse input Update time 1 day Sensitivity 50
Average pulse rate is 1 pulse per hour, with peak rate of 20 per hour, for 10 hours, three times per year.
No. of change messages (normal rate) = 0 (time for 50 pulses is more than the update time)
No. of change messages (peak rate) = 3 (three per year) * 200 (20 per hr for 10 hrs) / 50
= 12
No. of update messages per year = 363 (approx)
Total messages for pulse input = 12 + 363 = 375
Analogue input Sample time 1 hour Warm-up time 5 secs
Sensitivity 3% Update time 1 day
Average changes of >3% is twice per day
No. of change messages per year = 2 (twice per day) * 365
= 730
No. of update messages per year = 0 (always be a change message each 1 day)
Total messages for analogue input = 730
Total input messages per year = 400 + 375 + 730 = 1505
Power consumed in transmissions = 0.005 * 1505 * 2 (2 transmissions per message)
= 15 mAHr per year
Power for analogue loop supply (assume average loop current is 12mA)
No. of analogue measurements per year = 365 days * 24 hours * 1(sample time)
= 8,760
Power for analogue loop supply = 0.012 (from above table) * 5 (warm-up time) * 8,760
= 526 mAHr per year
Power for pulse input
Average pulse rate is 1 pulse per hour (0.0003Hz), so power required = 0.06 x 0.0003 per day
= zero
Quiescent power
Power for quiescent current = 3.4 per day * 365
= 1241 mAHr per year
Total power consumption per year = 15 + 526 + 0 + 1241
= 1782 mAHr
Expected battery life is = 1700/1782 = 0.95 year
Note that battery life is shortened during configuration or diagnostics. When the serial cable
is connected to the 505K, the module does not revert to sleep mode and the power