A large, complex network can create a cascade of alarms. Some are unimportant, but others are critical. Look for a RTU that can automatically sort and prioritize this flood of information for you.
Nuisance alarm filtering:
Even the best NOC staff stops taking alarms seriously if they're bombarded with status alerts, oscillating conditions, and unimportant alarms. Look for an RTU that filters these out.
Custom combination alarms:
A low battery isn't a serious problem, and neither is a failed generator - but they're pretty serious when they happen at the same time. Look for an RTU that can watch many different alarm inputs and spot critical alarm combinations.
Root cause analysis:
Finding the underlying cause between alarm cascades can take hours of patient detective work. Look for a RTU system that can automatically correlate repeated combinations of alarms.
History and trend analysis:
Identify problem areas and eliminate recurring problems with a RTU system that keeps a complete alarm history that's exportable for trend analysis.
Live analog monitoring:
You can't adequately monitor battery levels, temperature, and humidity with one-threshold contact closures. Look for an RTU that support for analog inputs, including live monitoring of actual analog values.
Many common site problems, from power outages to high temperature alarms, can be solved by quickly turning on a generator or an air conditioner. Remote operation of site devices is the best way to eliminate unnecessary site visits and it's a lot faster than going in the truck.
SNMP support and ping alarms:
If you're responsible for both telecom and IP equipment, consolidate all your monitoring on one RTU.
Another very important factor to take into consideration when deciding upon an RTU is looking at how alarms will be transported back to your control office.
Once alarm data has collected at your remote sites, it needs to be transmitted over a data network to your alarm presentation master at your NOC. Alarm data can be sent over nearly any kind of data transport: Ethernet LAN/WAN, dial-up modem, dedicated circuit, overhead channel, WiFi, etc.
There are two things you should keep in mind about RTU alarm data transport:
It is also important to note that the size of your network will determine the needs and requirements of your RTU:
Select a small remote alarm unit like the NetGuardian 216 for cell towers, remote huts, or enclosed cabinets (16 discrete alarms, 2 analog alarms, SNMP)
Select a medium remote alarm unit like the NetGuardian 832A for remote switches (32 discrete alarms, expandable to 176 discrete inputs, 32 ping alarms, 8 analog alarms, 8 control relays, 8 serial terminal server ports, SNMP)
For central offices or regional hubs, select a large remote alarm unit like the modular Advanced Telemetry System (scalable from 96 to 1,824 discrete alarms, 48 to 864 analog alarms, 32 to 576 controls, SNMP or TL1)