User's Manual

Configuring an A740 addNODE RTU in the addVANTAGE software
2.4 Configuring an A740 addNODE RTU in the
addVANTAGE software
To configure the addNODE RTU with an A840 Telemetry Gateway and the
addVANTAGE 4 Pro software, check the Base Station, Telemetry Gateway A840
and Wireless Modem A440 User Guide.
2.5 Maintaining and servicing the RTU
The A740 unit needs virtually no maintenance. The only part which might have to
be changed during the devices lifetime is the internal battery.
Since some sensors tend to drift over time make sure they are properly maintained
and calibrated or replaced if needed.
2.5.1 The RTU’s battery
The internal battery supplies 6.2 volts and consists of a 5-cell NiCd pack. The
internal electronics manage the battery charging/discharging process, ensuring it a
long life. This approach, coupled with a remarkably low average consumption
(some mere 6 mW for the standard RTU and 15 mW for the GSM RTU (not yet
available/Oct. 2004), allows an addNODE RTU to operate at least two weeks on a
fully charged battery, if the following conditions apply:
• The channel has moderate radio activity, with requests every 15 minutes.
• Total consumption of attached sensors is 100 mA or less.
• The sensors are not sampled more often than once per minute and only
one value per sensor is stored in the internal memory every 15 minutes.
The following table shows the A740 addNODE’s expected operating time on a fully
charged battery under various conditions. The sensor consumption does not
exceed 100 mA.
Radio Activity Sensor Sampling
(samples/15 min)
Average
Consumption (mA)
Estimated
Operation (days)
No No sensors 0.85 132
Low No sensors 2.8 40
Heavy No sensors 5 22
Low 3 4.2 26
Low 15 6.3 17
Heavy 15 9 12
Table. 1: addNODE Operating Time on a full Battery Charge
Note: Low radio activity means that one base station and between one and three RTUs
are active on the same operating frequency as the addNODE remote station.
Heavy radio activity means that approximately 30 devices are on the same
channel. However, no routing is used.
If for some reason (wear-out or accident) the battery loses its capacity (noted in the
software with repeated “Battery low” messages), it must be replaced. Make sure,
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