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How to monitor room temperature?

 
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Doug Dell
Advisor

How to monitor room temperature?

Hello guys,

I have been asked to come up with a means of monitoring the temperature in our datacenter. I would like to be paged if the temperature exceeds a certain value. Any ideas?

TIA,
Doug
9 REPLIES 9
A. Clay Stephenson
Acclaimed Contributor
Solution

Re: How to monitor room temperature?

Hi Doug:

There is an instrument that will do this; I think it's called a "thermometer". Sorry, I couldn't resist. Most data center HVAC system have a means to monitor termperature (and humidity) and either alarm or close a pair of contacts which can be sensed when the lits are exceeded. You could use the contacts to assert DTR (Data Terminal Ready) while trying to open a serial port.

Plan B: Get yourself a digital thermometer with a serial port that you can query. One I have used is an Extech.

http://www.extech.com/WhatsNew/PDF_datasheet/Datasheets_English/407401.pdf

If you are interested I could probably find the C code I wrote to query the device.

If it ain't broke, I can fix that.
S.K. Chan
Honored Contributor

Re: How to monitor room temperature?

The one we're using is from Pinnacle Technology. It's web based and provides real time temp data. I think it comes with the software to enable various threshold notification.
http://www.pinnaclet.com/products/dataloggers/idtrh.html
Tobias Hartlieb
Trusted Contributor

Re: How to monitor room temperature?

Hi Doug,

the HP9000 boxes don't have a readable temperature value. However, there is a temperature sensor in the systems, but this will issue only an interrupt when certain levels are exceeded.
Temperature levels for this interrupt depend on system, but are ususally around 35 degree Celsius - inlet temperature! This might well be some degrees above room temperature, depending on location in rack, etc!
The interrupt is handled by 'envd': cf. /etc/envd.conf ...: By default, events are logged into syslog.log.
Also, EMS (Event Monitoring System, part of Online Diag) will report an OVERTEMP event. EMS can be configured to send Email, write into files, etc..

There are few devices, which can be used for constant temperature reading: Some disk systems like SC10 or DS2300 and some Power Trust II UPS have means to read the current temperatures measured by those devices.

I hope this helps for a start...

Regards.

Tobias
Alexander M. Ermes
Honored Contributor

Re: How to monitor room temperature?

Hi there.
We are using some lines in the envd.conf.
Sample :


OVERTEMP_CRIT:y
/usr/bin/mailx -s OverTemp-Detected mailrecipient



OVERTEMP_EMERG:y
/usr/bin/mailx -s OverTemp-Detected mailrecipient
/sr/sbin/reboot -qh


FANFAIL_CRIT:y
/usr/bin/mailx -s Fan-fail-detected mailrecipient


FANFAIL_EMERG:y
/usr/bin/mailx -s Fan-fail-detected mailrecipient
/usr/sbin/reboot -qh


END OF SAMPLE


Rgds
Alexander M. Ermes





.. and all these memories are going to vanish like tears in the rain! final words from Rutger Hauer in "Blade Runner"
Doug Dell
Advisor

Re: How to monitor room temperature?

Hi:

Thanks everybody for the excellent ideas. I like Clay's idea for the digital thermometer with the serial port. The price is under $200.00 and that is especially attractive. Clay, would you please post your program/script that reads the thermometer?

Thanks,
Doug
A. Clay Stephenson
Acclaimed Contributor

Re: How to monitor room temperature?

Here you go Doug. You will need a very simple cable. The Extech thermometer has a mini-phone jack output so you simply need a 2 conductor + shield serial cable (I found my cable spec's and the comments in the C code explain the data format; no handshaking is needed the device simply outputs the data stream every few seconds):

Extech RS-232C DB25M
Tip 2 -- RxD
Ring 7 -- Signal Gnd
NC ---- Shield 1 -- Chassis Gnd

Here's the code, readtemp.c.

It's ANSI so you mmay need to convert the functions to K&R syntax if you done have an ANSI C compiler (or C++).

cc readtemp.c -o readtemp

Invoke as readtemp -u for usage.
If it ain't broke, I can fix that.
Bill Hassell
Honored Contributor

Re: How to monitor room temperature?

While using a computer to monitor temperature and then rely on a working network to send email to a constantly monitored email destination might seem like a good idea, is it worth risking 10's to 100's of thousands of dollars of comuter equipment with so many points of failure? Clay's suggestion of a lowly thermometer is the right direction. Trying to use a computer to protect a data center is asking for trouble.

Start with your air conditioning system. Is it just a dumb cooler or does it have failsafe capabilities that will shutoff data center power when a serious failure occurs? There are a number of temperature sensitive circuit breakers available that can remove power before serious damage occurs. Many data centers will rise to well over 130 degrees F in just a few minutes with total loss of air circulation. This could resuit in total loss of all equipment before anyone could respond to the emergency. I found an oscilloscope with solder dripping onto the floor of a sealed environmental chamber. The chamber was turned off but the scope disappated about 350 watts of energy over the weekend and raised the chamber to well over 600 degrees. The scope was junk.

So look at temperature safety equipment based on the cost of failure and look at equipment that is designed specifically to protect against over-temperature extremes. Have the power disabled to the data center before damage occurs.


Bill Hassell, sysadmin
A. Clay Stephenson
Acclaimed Contributor

Re: How to monitor room temperature?

Hi (again) Doug:

I think I will take this opportunity to amplify Bill's comments. The right way to do this is to have your HVAC systems (and fire detection equipment) able to completely disable the data center's power OR be so redundant (except for fire detection) that you don''t have to worry about it. I always have redundant HVAC systems so that the complete failure of one unit can be tolerated. I don't even allow the installation of a single unit which houses two independent systems. I make sure that they are truly separate units. It's still a good idea to monitor the temperature with a thermometer because you can then spot problems before they arise. If my data center temperature rises by more than 1.5 degrees F, I know that something is wrong and that is where data logging with a separate thermocouple for each unit is handy. In addition, a set of contacts in each HVAC unit can trigger a VP/O alarm. I also use a similar set on contacts to notify me when we are running on the diesel generator.


Also, the monitoring system should NOT be a critical production server. I dedicate a box to VantagePoint Operations and backup. The failure of this box might be inconvenient but it wouldn't kill production. On the other hand, if the monitoring system is also a critical production server and it fails, how will you know?

Bill also touched on another issue. It is dumb to RELY upon a network based email system to notify you of problems. The smart way to do this is to use email as the primary means of notification but to supplement it with a modem and a dial-out line if the primary message is not acknowledged in a timely manner. In my case, the dial-out can send numeric messages directly to my pager and my convention is that any code that starts with a '9' is critical and needs immediate attention. In this way, even a total network failure will not prevent the transmission of critical pager messages.

Remember, just because you don't think they are out to get you doesn't mean they're not.

Paranoid food for thought,
Clay


If it ain't broke, I can fix that.
Karoliuz
Occasional Visitor

Re: How to monitor room temperature?

Hello,

For monitoring server / data room I am using GSM control panel. It can monitor temperatures and can send information by SMS to several numbers. Furthermore, it can be used as alarm system for security, power failure, fire protection or even control electrical devices through SMS (ex. power on conditioner). System can be configured by SMS or configuration tool via USB.
More information about this device can be founded http://www.eldes.lt/en/gsm-remote-control-alarm-systems/esim262.html