Temp Alert: An Early Warning From RTUs Or Master Stations

Your sites must have some form of temperature control to ensure an optimum operating environment for your equipment. If your equipment gets too hot (or, however unlikely, too cold), it is likely to malfunction or even break, resulting in expensive repairs, and network down time. You should not have to wait for equipment to overheat to know that you have a problem. You need a more proactive approach to temperature monitoring. Your remote alarm monitoring and control system needs temperature alerts.

Temperature Alert message scenario
HVAC failures should generate Temperature Alert messages

Message Generation

A temperature alert is a message normally sent from a remote telemetry unit (RTU) monitoring an analog temperature sensor, or from a master station that is polling an RTU with a temperature sensor attached, notifying you of dangerous temperatures for your equipment. The temperature sensor itself is a relatively simple device that measures voltage readings. The reading changes as the temperature rises or falls, and your RTU will interpret the voltage output from the sensor as a temperature value based on reference values you provide (i.e. 2.5 V = 60*).

When setting temperature thresholds, remember that you want to know when you have a problem, but you also want to know before you have a failure. You want to leave yourself plenty of time to respond to a temperature alert based on the severity of the problem. So set the minor over threshold at just above the set-point for your temperature control systems. This way, if your temperature control systems fail at a site, you'll have time to fix the problem before an outage or equipment failure occurs. Set your upper thresholds to an alarming level, near the top end of your site's temperature tolerance, but far enough below a damaging temperature that you can respond to the problem.

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A DPS Remote Telemetry Unit real-time analog gauge

Remote Telemetry Units (RTUs)

Your better RTUs, like the NetGuardian series, are capable of monitoring multiple temperature sensors, or analogs of other types. Some RTUs have built-in temperature sensors or a connection for an external temperature probe, which can be used to monitor ambient temperature or the temperature inside your sensitive equipment. With multiple analog inputs, you can either connect multiple temperature sensors and measure temperature around the room, as you would in various spots in a data center, or monitor for other conditions at your site - humidity, wind speed, direction, fuel levels in your generators, and so on.

DPS Telecom recommends the NetGuardian series remotes because they can monitor and send temperature alerts for four different temperature thresholds: major under, minor under, minor over, and major over. When the analog sensor senses a value across any of the four thresholds, the NetGuardian will set an alarm. The threshold crossed will help you determine the severity of the problem at your sites (minor threshold values being bad but not catastrophic and major threshold values being the sorts of problems that require your immediate attention).

To prevent nuisance alerts, you can also set qualification timers as well. Qualification timers tell your NetGuardian RTU to set an alarm only when a condition has been present for a certain period of time. For example, if you set a minor-over alarm to just above the set-point for your air conditioning system, you could likely receive an alarm before the air conditioning has taken affect, which would be relatively meaningless. If, however, you set a qualification timer on that threshold for 5 minutes, then, if you receive an alarm on that minor threshold, you'll know that either your air conditioning has not come on or it is not effectively cooling your site, which is much more useful information.

You see, you don't want to simply monitor temperature. You have more important things to do than watching minor temperature fluctuations. You want your temperature alerts to let you know when you actually have a problem, and you want to know the severity and nature of that problem - not simply that the temperature is too high or too low, but how high/low and at least some indication as to why.

Of course, if an alarm goes off, it's no good if you (or another responsible technician) never find out about it. You need to be able to get temperature alerts from wherever you are. NetGuardian remotes can send pager or email notifications to let you know about the conditions at your site. Email notifications from NetGuardian RTUs are also acknowledgeable simply by clicking a link in the email. So, from your smartphone or laptop, you can still keep an aware of the situation at your sites.

Temperature Alert Message source options
Temperature Alert emails can be sent by RTUs or Masters.

With an accessory like the SiteDialer, you can have your NetGuardian send voice alerts when a temperature threshold has been crossed. The SiteDialer and similar accessories allow for DTMF access to your RTU, so you can call your alarm remote, check the status of your site or acknowledge alarms just by making a phone call.

Once you receive an alert, or simply to satisfy your own curiosity, you can access your NetGuardian remote by web to check temperature values monitored by your sensors in real time. If you have a NetGuardian remote, it's likely that the unit has at least a couple of control relays, and if your NetGuradian's relays are wired to your site's HVAC systems, you can operate HVAC equipment directly from the web, solving your temperature alarm without having to make a trip out to a site.

Master Stations

If you have a number of sites and are monitoring temperature (among other things) at multiple locations, you'll need a master station, to poll and consolidate monitoring of your temperature sensors and other alarms. While alerts from an RTU may be more helpful than not receiving notification for high temperature at your site at all, having to remember which of your sites the alert came from, the location of the site, set point for your air conditioning, and other factors that will contribute to you better understanding and rectifying the alarm situation, will take to long when you have a real emergency. It leaves too much room for error. Your master station, polling your sites and sending alerts, can give you access to more specific information about your sites and offer a single point of contact, making things easy on you.

DPS Telecom recommends the T/Mon alarm master platform because it can send escalating temperature alerts. With T/Mon, you can configure multiple notification methods for a site and have them sent in specific order. If the first-notified person does not respond to the alert and acknowledge the alarm within a period of time you define, an alert goes out to the next technician. This way, if you do get a temperature alert at your sites, you can make sure that someone finds out about it and create a chain of command at your sites.

Like the NetGuardian RTUs, T/Mon also has an accessible web interface that you can use to view your temperature readings and set controls to operate HVAC equipment at all of your sites. However, T/Mon also offers a graphical user interface called T/GFX. T/GFX is a map-based system that shows you where alarms occur by geographical location. The same interface allows you to "drill-down" to get a closer look at your sites, all the way down to the floor-plan and equipment views. This will help you and your technicians pinpoint the problem when you receive a temperature alert.

The idea is not simply to receive an alert when the temperature at your site reaches a critical level, but to be able to pinpoint the problem and fix it, so you can save your expensive equipment from damage and keep your network operational. Temperature sensors connected to RTUs and Master Stations that provide progressive notifications and simple interfaces can help you keep a closer eye on your sites, so you can decrease the cost of maintenance (and site visits) and increase network uptime.

Related Topics:

Temperature Sensor

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