| Author | Message | ||
     Francesco Davini (franz) Junior Member Username: franz Post Number: 9 Registered: 2-2009 |
Dear Dr. Balamurugan, Lamps in general suffer from repeated switching on and off. Some instruments may have electronics to smooth the thermal and electrical shock to the lamp at each switch, but in general it is better to leave it on the whole day if you plan to make analyses hourly. Also, most instruments reccomend a 30 minutes warm up time before making an analysis and this should be taken in account. Differences exist between instrument brands regarding lamp's lifetime, design (and cost!) thus about how to operate it. I suggest you contact your supplier's specialist to have suggestions, but I'd bet that the answer will be to have the lamp always on if the istrument is operated 24/24 and 7/7. Personally I would recommend switching off the lamp only when analyses are not needed for over 6 hours, but again this is very instrument dependant and you should follow manufacturer's reccomandations. Best regards Francesco | ||
| venkatarman (venkynir) Senior Member Username: venkynir Post Number: 113 Registered: 3-2004 |
Dear Dr.Balamurugan ; 1. Switch it and off every one hour (or) If you operated in pulse mode the life is better but we have to take care of stablization time in to out and source may take high current from cold to hot condiitons. 2. Switch on the lamp and let it in same status for 24 hours. If so, how long/days we can keept it switch on. Genarl lamp life has 1000 hours and under operating it life is little more . venkataraman | ||
| BALAMURUGAN.R. (suguna) Junior Member Username: suguna Post Number: 7 Registered: 4-2006 |
Hi Everyone, I use NIR in feedmill wherein production is 24 hrs continuous running. So I need to scan samples for every 1 hr once. In this case I have doubt on NIR lamp lighting hours. Which of the below will help to extend the life of lamp. 1. Switch it and off every one hour (or) 2. Switch on the lamp and let it in same status for 24 hours. If so, how long/days we can keept it switch on. Dr.Balamurugan | ||
| Hermudananto (hermu_hela) New member Username: hermu_hela Post Number: 2 Registered: 11-2008 |
Hello Tina, I ussualy check our lamp condition with these indication on wavelength graph (see attach).If your apparatus show that graph, you must change your lamp. In gain test commonly stable on the range 2,3-5,7, so your apparatus is indicate less/more from above for VIS and NIR, right. In check cell, contain mix organic material which have already know the standart value (for several years, about 5 years expire date). i.e. our check cell contain : CONSTITUENT VALUE DEVIATION protein 45,4 +-0,3% fat 3,9 +-0,1% DF(fiber) 4,0 +-0,3% drymatter 92,8 +-0,1% so, if I do check cell everytime, these standart value above is indicate that our apparatus is running in good performance. add with Diagnostic Test everytime, to see our wavelength, bandwidth, and noise test is still in good performance or not (PASS/FAIL). So, before and after you change your lamp, you should do wavelength analysis, diagnostic test, and check cell. I'm just know NIRS for 2 years, and my knowledge is still basic, I need learn more and more for this,but like to share my knowledge to everyone who interest in NIRS. I hope it sufficient for you. regards, Hermu  | ||
| Tina (tt200878) New member Username: tt200878 Post Number: 2 Registered: 7-2008 |
Hi,everyone,thanks for your information,I very appreciate it.I am also using Foss instrument with ISIscan as operating software,and this modle only have NIR part,up to now,I have not noticed any obviously changes about the check cell's spectrum,but I run gain test provided by the software periodically, and I found the voltage is very high, so I suspect that maybe the lamp need to change after certain time.If I need to change I will follow your suggetions,scan foss check cell and standards before and after I change the lamp, and comparing the correspongding spectal to determine whether restandardization or not. | ||
| Hermudananto (hermu_hela) New member Username: hermu_hela Post Number: 1 Registered: 11-2008 |
Hello Tina, I have been changed the lamp for 2 times during 2007-2009, but it depend the problem of your apparatus. We have also discussed it with NIRS expert in france, he said to us, there are no rule/limit changing the lamp, we can check it with check cell/diagnostic test (in ISIscan FOSS) if you used it. so, it depend once again as far as I know. And after we change the lamp (by our self), not by NIRS technician, we always do check cell and diagnostic cell to know that our NIRS apparatus is good work. just it..hopefully it helpful for u. regards, hermu | ||
| JUAN GARCIA OLMO (jgolmo) New member Username: jgolmo Post Number: 5 Registered: 6-2007 |
Hello Tina, the procedure is quite different depending of the instrument you have. As a general rule, you should check the spectra of a standard sample (i.e. check cell sample for Foss instruments) before and after you change the lamp. So, it is very important to obtain spectra of a standard or sealed sample with the different lamps of your instrument. If the spectral differences are very high (estimated by using the RMS error), it could give different NIRS predicted values. In this case, you will have to develop a stadardization procedure between both instrument situations. | ||
| Michael Kinsey (mike_kinsey) New member Username: mike_kinsey Post Number: 5 Registered: 1-2009 |
Tina, Hi there, our lamps for xds nir, which are bench top instruments, usually last over two thousand hours-ish some longer some shorter, sometimes they have a mind of their own, the instruments which are continuosly left on, not running continuosly but on. When I change the lamp after failure I have to recalibrate the instrument using a set of standards that are supplied with the instrument this is also true for when the instrument is moved to the factory when a breakdown occurs, this step is fairly easy to perform, as with our instruments they come with a bracket and lens, and the instructions of how to calibarte should be in the manual, try using the help menu if you are unsure. Really the service engineer will only have to change intensity of lamps when an internal part has failed, for example encoder motor arm or mirror. With our instruments we tend to leave them warming up for several hours before we even consider recalibrating with the standards. You will start to see a drift in the spectra of tailing of in the VIS range if the lamp is on its way out, this is an early warning sign if you like. I would consider changing the lamp as really the lamp intensity is a crucial factor when scanning samples, as the conditions have to be similar to what they were when the calibrations were made. | ||
| Tony Ainscough (tony_ainscough) New member Username: tony_ainscough Post Number: 5 Registered: 5-2009 |
Hi Tina, there are very few modes of failure for a tungsten halogen lamp. The most common mode is obviously complete failure. There are several lamp designs in use in NIR equipment these have varying figures for mean time between failure but this normally amounts to 1000hrs+. As you have pointed out some manufacturers have employed methods for altering lamp intensities by adjustment of lamp voltage but this is a task normally performed by a service engineer. You would need a reference spectrum to compare with in order to be sure your energy throughput was as before. Have you noticed a change in the instrument performance which has prompted you to suspect the lamp intensity? Regards Tony | ||
| Tina (tt200878) New member Username: tt200878 Post Number: 1 Registered: 7-2008 |
Hi,everyone,A question about changing a new lamp,do I need to re-standardization NIRS scanner if I change the lamp, and what is the best time to change lamp,because the voltage of my lamp is quite high, but still in the receptable range,and I don't know how long the old lamp can be used if I only operated the scanner 12-18 hours a week.Thanks for your help in advance! |