Monitor Your Room Temp with TempDefender IT

You know how important it is to monitor your server room temp or data center temp. If the temperature rises too far, you can suffer expensive equipment damage and service downtime. Installing a device to monitor your room temp is one of the most powerful investments you can make to protect your valuable IT infrastructure. You'll sleep better at night knowing that you will be alerted automatically if temperature rises too high.

Since you're reading this article, you've already given yourself a big advantage over other people with server rooms. Many network professionals fail to recognize the importance of monitoring room temp. They simply trust that "the AC units are reliable" or "we really don't have that many servers. Unfortunately, experience is a cruel teacher, and these people are simply rolling the dice until they face the massive expense of servers overheating.

In this diagram, an HVAC (air conditioning) failure occurred without knowledge of the network operators. No server room temperature monitor was in place to detect and report the high temperature, so equipment damage and data loss will result in expenses that could have purchased literally thousands of room temperature monitoring devices...

This is regrettable because it's entirely preventable. Room temp sensing and reporting devices are not at all expensive when you consider the value they provide. They're also quite simple, generally consisting of a small (but reliable) monitoring box that will report alarms in a few simple (but customizable) ways.

Let's review some industry best practices for room temp monitoring. If everyone followed this advice, servers would encounter far fewer thermal shutdowns and related service outages.

First, any room temp monitor should use analog temperature sensors, not discrete sensors. This allows the device to monitor and report the actual temperature at all times, not just whether the temperature is "above" or "below" a preset level.

Second, any device to monitor your server room temp must allow you to set temperature levels that represent the upper and lower limits of acceptable temperature. Even better are monitoring devices that support multiple upper and lower limits (major and minor for both upper and lower, for example).

Room temp monitors for IT environments commonly have a different sensor connection method than temp monitors for industrial telecom, although both styles can function reasonably well in either environment. IT room temp monitoring devices typically use a "daisy-chain" architecture for their sensors. Commonly known as either "1-wire" or "D-wire" (since all data from a daisy chain of sensors is transmitted on a single wire), this architecture is convenient when multiple sensors must be located at various distances from the monitoring device in several clusters. A single wire connects the first sensor in the chain to the room temp monitoring device, and then other wires can simply connect the second sensor to the first, the third to the second, and so on. One big advantage of these daisy-chained sensors is that power is also provided over the single wire.

TempDefender: Protector of the Server Room

To monitor temps within the server room from a single device, the TempDefender IT is recommended. The TempDefender is a small, rack mountable remote telemetry unit (RTU) that can handle up to 16 analog sensors reporting on all of the environmental factors in your server room. Sensors for the TempDefender may be daisy-chained together, so you don't have to run a mess of cabling back to the TempDefender. You can also string sensors up to 600 feet away from the TempDefender IT RTU, allowing you to run sensors to the most extreme spots in your server room from a centrally located device without worrying about the connection strength.

Industrial telecom room temp monitors more commonly support analog sensors in a standard "star" topology, where each sensor is directly connected back the central device for data logging and transmission. Obviously, this can be advantageous or disadvantageous depending on the physical layout of your room where temp must be monitored. If you do choose the architecture, regardless of your industry, it's highly recommended that you select a room temp monitor that supplies power (typically +12v DC is required for standard temperature sensors) directly to a sensor. Otherwise you'll generally need to use bulky wall transformers to power what are otherwise quite compact temperature sensors.

It's also very important that your room temp tracking scheme including history logging and trending capability. The software features really take your temp monitoring to the next level. It's one thing to know that the temperature is high right now, and that is 1000 times better than knowing nothing at all. But if you're able to view the room temp values as a line graph in recent history, you can diagnose cyclical or growing problems.

For example, if the climate in your area is rapidly becoming a warm summer, you might notice that the line graph is gradually rising. This kind of intelligence could prompt you to install additional HVAC units, turn up the ones you have, or otherwise respond to the temperature threat. You might also notice a daily cycle in your room temp. It's easy to understand that the hottest times of the day might correlate with the hottest temp in your server room or data closet.

The TempDefender IT is a good example of a room temp monitoring device. It supports up to 16 daisy-chainable temperature and/or humidity sensors. The internal firmware supports 4 user-configurable temp thresholds (2 upper and 2 lower). The chassis size is small at 1 rack unit high and a narrow width.

Daisy-chainable sensors (known as "D-Wire sensors") are connected to the four digital ports on the TempDefender's back panel. This allows a hybridization of the two architectures described above. Up to four D-Wire sensors may be connected directly to the TempDefender, while others can be daisy-chained to those first four in any configuration as long as the total limit of 16 sensors is not crossed. This means that it's possible to daisy-chain 16 temp sensors from a single TempDefender port in one long chain, or you can distribute the sensors more evenly across the four available ports. This design supports maximum flexibility for monitoring room temp.

While you can receive high/low room temp alerts via email or text message (and this will be the ideal notification type for many smaller companies), the TempDefender is also "future proofed" because it can send SNMP traps to an SNMP manager. Virtually all medium and large IT installations include a software and/or hardware SNMP manager to track and respond to the real-time status of their equipment and related conditions, especially server room temp.

The TempDefender also has 8 traditional discrete (also known as "digital" or "contact closure") inputs for monitoring your equipment. This can be used for general equipment monitoring, but it's also very useful in a room temp monitoring system to monitor your HVAC status. Using several of these 8 inputs you can determine whether each HVAC unit is running (rather than trying to make a secondary determination based on temperature rising). With this sort of redundant monitoring, you'll be able to address an impending temperature rise immediately after the AC systems fail, rather than waiting for the temperature to rise to the top of your acceptable temperature range. This buys you additional time to handle the problem. In a room temp crisis, time is everything.

How DPS Telecom Clients Monitor Their Room Temps
Over the years, DPS Telecom has accumulated quite a few real-world stories of room temp monitoring scenarios. DPS clients have consistently discovered that monitoring room temp is one the most effective protections against equipment failure caused by environmental conditions (rather than intrusion, routine hardware failure, etc. which are typically also monitored by the same device that monitors temperature).

As I've described, data centers are excellent places to deploy temp monitors. Servers and other network hardware produce large quantities of heat whenever they are running (typically 7x24x365). To push your uptime up toward 100%, you must monitor temperature 100% of the time.

One client approached DPS after have significant trouble stemming from unmonitored room temp. His AC units had been failing to operate as desired during the previous quarter of the year. Although he was not sure of the cause, this didn't matter much. The threatening temperature conditions, unchecked by a climate control system, were causing failures. In fact, at the time this client came to DPS, he had experienced yet another incident within just the last week. He needed a room temp monitoring device that would call or send a text message (SMS) to his mobile phone at any time that a runaway temp was detected in the server room.

Some DPS clients in arctic climates also find that using NetGuardian RTUs to monitor for frigid room temps can be just as effective as monitoring for heat. The biting chill of arctic conditions can, in fact, be just as damaging to your site equipment as heat can.

DPS also conducted a deployment with a telecommunications company to issue room temp alert notifications from unmanned locations via a single T1 line. A NetGuardian uses just one DSO. This means that a large number of these alarm remotes may send alarms to an alarm aggregation console like T/Mon with only one T1 available.

But it's not just big telecom firms that monitor room temps. Another DPS client in the eastern United States used a POTS-based RTU that would simply call the "on-call" technician whenever temperature rose too high. Although only a pair of technicians were databased into the system (via the NetGuardian's built-in web interface), more than half a dozen call recipients may be configured into NetGuardians with voice dialing capability.

IT pros in the railroad industry have also been known to deploy NetGuardians to support network systems for train dispatching and management. Railroads commonly place equipment into track-side huts and small metal enclosures. Since these locations do not include any form of AC or heat, a NetGuardian with an extended temperature tolerance was selected. This is a NetGuardian whose standard internal components have been replaced with stronger components that have a higher temperature tolerance. Said another way, the relatively weakest links in terms of temperature tolerance have been strengthened to improve the resistance to room or enclosure temp of the overall monitoring device.

Related Topics:
Environmental Monitoring
Server Room Temperature Monitoring

Related Products:

• Vaisala - Temperature/Humidity Sensor
• NetGuardian 832A (Large RTU to support multiple temperature monitors and other equipment alarms)
• TempDefender IT (Compact temperature monitor device designed for server rooms and data centers)

Monitoring Computer Room Air Conditioning Systems with TempDefender

Tips for Server Room Temperature Maintenance and Monitoring

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NetGuardian 832A