A:
The Power and Energy Meters will then sample at close to its maximum frequency. For instance when measuring 10 KHz with a PD10 Sensor and Nova II where the maximum frequency for every pulse on the Nova II is 4 KHz: in this case, the Nova II will pick out pulses at a rate of close to 4 KHz and sample them, i.e. the Nova II will record 40% of the pulses.
A:
It can work with any sensors in dual mode where they are operating
separately but for ratio or difference it can only work
with pyro vs. pyro or thermal/photodiode vs. thermal/photodiode.
A:
This can sometimes happen when the battery of the Power and Energy Meters
is completely discharged and then the charger is plugged
in. The Power and Energy Meters is powered up but the contrast voltage on
the LCD is not functioning, so it looks as though it is
off; and usually the backlight switches on and off normally.
The solution is to first switch OFF the Power and Energy Meters properly
by pressing the On/Off button for 4-5 seconds, and then
switching it back ON by momentarily pressing the On/Off
button, as normal.
The Power and Energy Meters will also fail to operate if you attempted to download
a software upgrade and there was a malfunction in the download,
see the question "Can I upgrade " below.
A: The Power and Energy Meters software can be upgraded by the customer using Ophir's USBI
PC application available for download from the Ophir
website.
1.
Attach the Power and Energy Meters to your PC with the
USB cable provided with the Power and Energy Meters.
2.
Go to the bottom
of the USBI
page and download the firmware for your Power and Energy Meters
3.
Run the USBI
PC application
4.
Select your Power and Energy Meters device and press upgrade
5.
Application
will open the "Device Upgrade Screen"
6.
Follow all
the on-screen instructions to successfully reprogram
the display.
If
the field-upgrade process fails (example, unplug of
the USB cable during the upgrade), the Power and Energy Meters will
not function properly. Therefore, when turning on
the Power and Energy Meters the user gets a blank screen. Note: The
Power and Energy Meters can still communicate with the PC. Try to
reinstall the Power and Energy Meters software as described above.
A:
Think of it like a voltmeter or ammeter, these have to be recertified/recalibrated as well like most other pieces of test equipment. In general, our instruments are unlikely to drift or fail over time like a sensor might that is constantly exposed to laser energy. But the possibility exists. So the general practice in our industry is to have Power and Energy Meterss recalibrated and recertified as well. ISO standards and FDA, as well as other agencies, require both be recalibrated and recertified.
A:
Clearly there are many possible power/energy distributions, and laser damage to a sensor can occur at a local peak power density spot even if the overall
power density is within spec. Ideally, then, a damage threshold spec should depend on what the beam profile is. However, it is very difficult to calculate what
the peak power density will be at the center of a beam unless it is a uniform ("top hat") beam - which is seldom the case. Further complicating things is the
fact that a laser spot's borders are not solid lines but rather have a certain "fuzziness", which is why modern beam profiling equipment offers a variety of
mathematical definitions of beam size when measuring a profile.
In order to provide users with a useable, practical guideline, we do define our specs in terms of a uniform distribution. However, when we determine the actual
damage thresholds for our sensors, we take a level of safety margin into account, so that for "typical" beams whose profile is not too complex our spec will
roughly reflect the peak power density of the beam. As a further safety measure, we also always recommend that users choose a sensor that, all other things
being equal, will work at not more than 50% of the specified damage threshold.
Close
A:
The Ophir specification on accuracy is in general 2 sigma standard deviation. This means, for instance, that if we list the accuracy as +/-3%, this means that 95% of the sensors will be within this accuracy and 99% will be within +/-4%
A:
If the power is P and the diameter of the beam is D then
the power density is P /(.785 * D2) . If it is a pulsed
laser and the energy is E, the repetition rate is R and
the diameter is D then the power density is E*R/(.785 *
D2), The energy density is E/(.785 * D2)
A:
If the calibrated wavelength is W1 and I want to measure
at wavelength W2 then I look at the relative sensitivities
on the curve at W1 and W2 and calculate as follows: Sensitivity
at W1: s1 Sensitivity at W2: s2 When instrument is set to
W1 and I measure W2, then multiply reading at W2 by s1/s2
to get correct reading at W2.
A: It varies from sensor to sensor. In general, the uniformity is better than +/-2% over the central 50% of the area and for many sensors considerably better than this. For detailed information, please consult your Ophir representative.
A: There are in general no losses associated with using our fiber optic adapters. The adapters are simply jigs to hold the fibers in the right location vis a vis the measuring sensors. They do not transform the beam coming out from the fiber in any way.
A: With normal usage we recommend calibrating every 12 months. To accommodate shelf time and shipping time new manufactured product comes with a calibration sticker that shows a recalibration period of 18 months from manufacturing. However this does not negate the recommended 12 month recalibration interval should you receive the product with more than 12 months remaining on the new manufactured calibration sticker.
A: All Ophir power meters, including photodiode power meters, have an air gap between the fiber tip and the sensor. Therefore they measure the power emitted by the fiber into the air and do not take into account any reflection losses there are in the fiber. Therefore, if in actual use, the fiber will be coupled with no loss to another element, then the losses should be added to the reading. These losses are usually about 4%. Thus if the reading on the Ophir meter is say 100mW, then in lossless use, the real power will be 104mW.
A: All lasers or optical delivery systems degrade over time. A Power and Energy meter will help verify this and quantify this over time. It's a diagnostic tool to ensure that the laser system is delivering the specified amount of energy or power. The precise measurement of energy may critical in many of the processes in which they employed.
A: They start looking for causes, like lenses degraded, output couplers degraded, bad fiber, bad power supply. Many call their customer service party, whether it' s the laser company or and independent field service org.
A: Yes, I'd say that many newer industries like aesthetic lasers may not have that awareness that what actually comes out of the laser delivery system may vary dramatically from what the internal monitors displays what is coming out.
A: This depends on whether you are using a thermopile sensor head or a photodiode sensor head. With our most sensitive thermopile sensor head, model 3A-FS one can measure down to 20 uW. With our photodiode sensor heads we have a couple of different types, silicon, InGaAs and Germanium. Each have a spec on minimum power, which can be in the nW or even pW range.
A: For pyroelectric energy sensor heads there is no limit on how short the pulse is, as they are integrating devices. As long as one does not exceed the damage threshold expressed in terms of energy density then they will accurately integrate pulses as short as femptoseconds. With thermopile sensors they similarly can be used as integrating devices to measure energy, although one can only measure single pulses every few seconds as they have a much slower response time than pyroelectics. With repetitive short pulses one can measure the average power with a thermopile with no restriction on how short the pulses are, as long as the energy density damage threshold is not exceeded. The spec for damage threshold varies on type of absorbing surface of each sensor head type. Consult our damage threshold charts for detailed information.
A: The problem of irradiating the head with different input powers is analogous to that of filling a tank that has a hole in the bottom. The rate equation describing the accumulating energy (heat) in the head is
where P is the power incident on the sensor, is the characteristic time constant of the heat dissipation (thermal time constant) and Q is the heat in the sensor.
The complete solution to this differential equation is an exponential of the form:
The parameters in the above equation are determined by the head characteristics and the initial conditions.
For a generic head starting at room temperature this equation becomes:
where Pcont is the maximum power permitted for continuous operation. We can use the other known operating limits of the head to solve for , the thermal time constant of the head.
Here Pint is the power permitted for intermittent use for tint seconds. With we can calculate the permitted operating time for an arbitrary power.
For your case we have the known limits:
75 W continuous
500 W for 1 min
So Pcont = 75 W. Using Pint = 500 W and tint = 60 sec gives a value of = 370 sec. Combining we have:
which tells us how long we can irradiate the sensor (from cold start) for any given incident power.
With 150 W, you could irradiate the sensor for 250 sec.
However, if you want to cycle between irradiating and cool down continuously, you don't reach ambient before the laser is turned on again. If the laser is on for t(on) and then turned off (or blocked) for t(cool), the head will cycle between two values of Q: Q(max) at the end of the heating (related to Pcont) and Q(0) at the end of the cool down and start of the heating.
Using the general solution for Q above, we can solve for the behavior during the heating and cooling phases.
This leads to the following equation relating P, t(on) and t(cool):
where Pcont and are determined as described in the first case above. Note that the behavior is essentially the same as for the previous case in which we started with the sensor at ambient but with the maximum power permitted for a given irradiation time reduced to
You indicated that you want to take 10 readings of 20 seconds each so t(on) is 200 seconds. For incident power of 150 W and measurement time of 200 sec, we need a cool down time of 470 sec. Other parameter sets can be considered as necessary.
A: We have done some in-house tests with LabVIEW 8.2 and the USBI VI's seem to be compatible.
We've also had other customers working with our VI's in LabVIEW 8, so far with no clear issue that we know.
In fact, LabVIEW usually offers/suggests that it will automatically update the VI's when opened with a newer version of LabVIEW.
A: If you are planning on communicating with the instrument via RS232 (for those instruments having an RS232 interface), then the StarCom manual included on the CD-Rom includes a full description of device communication and commands.
If you are planning on communicating with the instrument via USB (for those instruments having a USB interface), then in the Installation Directory of the StarLab, you'll find a sub-directory called Automation Examples that contains within it examples of how to use the USBI ActiveX to communicate with the device. It also contains a document describing the various commands.
A: Device responses take the form 1.234 (a period distinguishes between the integer and fractional part of a real number). This may not match the settings of the computer upon which the VI is running. For example, many European countries use a comma (",") in place of a period (1,234). This causes the LabVIEW VI to not "understand" the devices's response.
(Go to http://zone.ni.com/devzone/conceptd.nsf/webmain/99d21982a9f954e186256a5b0057919e the section on Period and Comma Decimal Separators for National Instrument's explanation)
Solution: LabVIEW allows the User to override the local regional settings of the computer within the LabVIEW environment. To do so
A: At Ophir, we developed USB drivers for use with our USBI PC application. National Instruments USB drivers work in a different manner. Ophir drivers are not compatible with NI VISA communication. NI drivers are not compatible with Ophir's USBI PC application.
SwapINF configures Windows to associate the Ophir device with NI-VISA's usb driver (NIVIUSBK.sys) when LabVIEW is selected. It configures Windows to associate the Ophir device with the appropriate Ophir usb drivers (windrvr6.sys) when USBI is selected
REMINDER: To work with LabVIEW, NI-VISA 3.01 or higher (from National Instruments) must also be installed.
Click here to download
the self-extracting "SwapINF Utility". Run the SwapINF utility
and follow the on-screen instructions to configure the USB speaking
device (USBI or Nova-II) for LabVIEW or USBI PC work as desired.
A: Here are additional clarification steps to assist establishing the interface to LabVIEW when connecting an Ophir meter such as the USBI/Nova II/Vega with the USB.
The sequence for preparing to interface the Ophir USBI (or meters connected through USB) with LabVIEW is generally as follows:
BE SURE the OPHIR CD is NOT in the PC CD drive when running SWAPINF.
Disconnect any USBI OPHIR Device from the PC
Run SwapINF utility
Set LabVIEW option On
Press "Swap" button
You will be prompted to "Remove the Ophir USBI Devices before continuing"
Press "OK" (you have already removed these)
Press "OK" again (after SwapINF is done)
Reconnect the Ophir USBI device to the PC that you wish to apply LabVIEW VI's on
If asked by Wizard (i.e. in XP) to update software etc.
Select "not this time" & press "next" button
Again, press "next" (install software automatically)
From here on you may apply LabVIEW VI's on your device
A: The Ophir integrating sphere sensors, models 3A-IS, 3A-IS-IRG and F100A-IS have a white diffuse reflecting coating on the inside of the integrating sphere. The sensitivity of the sensor is quite sensitive to the reflectivity of the coating. If the coating absorption goes up 1%, it can cause a 5% change in reading. Therefore, care must be taken not to soil or damage the white coating of the sensors. Also it may be a good idea to send the sensors for recalibration yearly.
A: The BC20 has a peak measurement and hold circuit
which measures the peak power on the detector and holds
it. Therefore when a beam is scanned over the detector,
when the beam is on the detector it goes up to a peak which
corresponds to the same power the detector would measure
if the beam was stationary and therefore the BC20 reads
the correct power whether the beam is scanned or not. In
order for the BC20 to do this, the beam must be on the detector
(of size 10x10mm) for at least ~13µs and therefore this
limits the scanning speed on the detector to 30,000 inch/s.
A: No. We have carefully designed them that there
are no such effects from multiple reflections. This is because
we use only absorbing or diffusing type elements.
A: The reading jumps around a lot but if you use
the average function and the pulse energy does not exceed
the ratings in the sensor catalog, the reading should be okay.
A: It's +/-3% of the reading from full scale down to 5% of full scale. Below 5% of full scale one should switch to next range down for the best accurate linear results.
A: In general yes, but 2 technical issues need to be kept in mind (both of which are results of the fast physical response time of these sensors):
If the pulse frequency of your laser is close to the (typically 15 Hz) sampling rate of the power meter - say in the range of ten or several tens of Hz - there will be a "beat frequency", i.e. the reading will jump around and it will be difficult to get a good measurement. The solution to this is to use the "averaging" function. At higher pulse frequencies, the sensor will respond as if the beam were CW.
It is possible for a pulsed beam to have average power within the sensor spec and yet have the energy of the pulses themselves be high enough to cause a momentary saturation of the sensor. It is important to be sure that pulse energy is also within sensor spec (this parameter is included in all specs for the PD300 family, for just this reason).
A: All Ophir pyroelectric sensors can measure average power with Ophir Power and Energy Meters. The instrument measures the number of pulses each second and divides the energy reading by the pulse rate. If the pulse rate is constant, then the accuracy of power measurement will be the same as the energy accuracy since the pulse rate measurement is very accurate.
A: No, even though the scope adapter allows viewing of the actual electrical pulses coming out of the sensor and thus looking at higher repetition rates, the Power and Energy Meters is still needed to supply power to the sensor and to enable changing of ranges.
A: Ophir pyroelectric sensors have a positive temperature coefficient of 0.2% per degC which means that if the sensor heats up 10 degrees, the reading will be 2% high. The PD10 and PD10-pJ sensors use photodiode detectors so their temperature coefficient is the same as the PD300 sensors as listed on the PD300 pages of the Ophir catalog.
A: Our energy detectors measure the total energy deposited within a time window defined by the pulse width setting selected via the Power and Energy Meters. There is no minimum pulse width limitation since we are measuring the energy deposited, not power or peak power.
A: There is no reason not. Theuser will have to make
a vacuum tight 15 pin feedthrough to get the signal out.
We also sell a vacuum flange for the PE50 sensor
A: If the vacuum is not ultra high and the system
is unheated, yes. The user has to rewire the 15 pin plug
into a vacuum feedthrough or if possible, use the wireless Quasar interface.
A: We specifiy the linearity as +/-2% for >10% of
full scale. One can get reasonable accuracy down to 5% of
full scale but at 3% of full scale the readings will be
guaranteed to be considerably off. Therefore, the user should
always use the meter on the lowest scale that he can read
on and if there is a discrepancy between a particular heading
on the higher and lower scale, the reading on the lower
scale is correct.
A: The sensor will stop integrating after 50us and
will lose part of the pulse. It will then read low. This
is relevant to the PE10 which only has the short setting
(in the case of PE10 it is ~30us).
A: The Power and Energy Meters simply decides it is time for a sample
and takes the next pulse that comes after that time, e.g.
if it samples at 400 Hz, then every 1/400th of a second
it is ready to take the next pulse that comes along.
A: The problem is most probably acoustic vibration. Pyroelectric sensors are sensitive to vibration as well as heat. On the most sensitive scales of sensitive sensors such as the PE9 and PE10, they may be very sensitive to vibration. The solution is to put an acoustically absorbing material such as a thin piece of soft foam plastic under the base of the sensor to damp out any vibration.
A: The problem is most probably false triggering caused by acoustic vibration. If the pulse frequency as shown on the meter jumps around, then acoustic vibration is almost certainly the problem. Pyroelectric sensors are sensitive to vibration, and they in fact detect acoustic pulses through the same physical mechanism with which they detect laser pulses. On the more sensitive scales of sensitive sensors such as the PE9 and PE10, they may be very sensitive to vibration. You can see this by setting such a sensor to a low energy scale (e.g. 2 mJ) and clapping your hand once, just above the sensor's surface; you will get a reading. The solution is to put an acoustically absorbing material such as a thin piece of soft foam plastic under the base of the sensor to damp out any vibration; acoustic noise carries primarily through the base (rather than through the air).
A:
All USB speaking devices (Pulsar and USB Interfaces as well as the Vega and Nova-II Power and Energy Meters) can be controlled via our StarLab. This provides full remote control and measurement capabilities. In addition, system integrators can make use of the ActiveX components (UsbX for USB Interface, Vega, and Nova-II; FastX for Pulsar) that are included in the application installation. Documentation and Examples in Visual Basic, VC++, and Excel are found in the "Automation Examples" sub-directory of your StarLab directory. For the LabVIEW community of developers we supply the Ophinstr and DemoForPulsar libraries to get your LabVIEW VI solution started.
A:
The StarLab can support up to 8 sensors simultaneously. This can be through attaching 8 sensors to 8 different USB Interfaces, 8 sensors to 2 Pulsars or any combination in between. Note that when working with a large number of devices you may run out of ports on the PC. In that case, you must use a USB compliant Hub
A:
The Analog output for Pyro sensor can measure up to 10 Hz. Therefore if you want to measure at a higher frequency (up to the maximum frequency of the sensor), you can connect the Scope Adapter for Pyro sensor (Ophir P/N 1Z11012). This adapter provide a BNC output to scope to see every pulse up to the maximum sensor frequency. Note: The Pulsar device is not equipped with an analog output
A:
From StarLab, we support customer tailored OEM features as well as standard application features. If OEM is selected, the user will be asked to enter his OEM code. The OEM code is specific to each type of tailored interface ordered. If the code is entered, a special installation (with the requested features) will be performed. For all other customers, the Standard installation is the correct choice.
A: In general, the dynamic range, i.e. the ratio of maximum useable power to minimum useable power of Ophir OEM sensors is 40:1. If greater dynamic range is desired, Ophir OEM RS232 sensors are available with several selectable ranges.
A: The damage threshold of thermal sensors does depend on the power level and not only the power density because the sensor disc itself gets hotter at high powers. For instance, the damage threshold of the Ophir broadband coating may be 50KW/cm2 at 10 Watts but only 10KW/cm2 at 300W. The Ophir specifications for damage threshold are always given for the highest power of use of a particular sensor, something which is not done by most other manufacturers. This should be taken into account when comparing specifications.
A: We publish a nominal damage threshold for most
of our thermal BB sensors as 20KW/cm2. Other manufacturers
may quote higher numbers than this. In actuality, in one
to one tests against competitors, our sensors show a higher
damage threshold but the actual damage threshold depends
on the total power as well as the power density. For very
low powers such as 30W, the damage threshold can be as high
as 50KW/cm2 and at high powers such as 5KW, it drops to
3KW/cm2. The Ophir sensor finder program takes account of
these variations in its calculations.
A: The damage threshold curve in the sensors catalog
only goes down to 1ns but the energy damage threshold is
similar for shorter pulses. You can use ˝ of the ns value
for fs pulses i.e. the absorber damages twice as easily.
A: The 3A-P actually absorbs about 85% at 10.6µm
and therefore it can be used to measure weak CO2 lasers.
Note the low power damage threshold, however, of 50W/cm2.
A: UV: 193 - 350nm, VIS: 350 - 850nm, NIR: 850 -
3000nm, CO2: 10.6um. Newer sensors have the regions explicitly
where the laser settings are: <.8µ, .8-6 and 10.6
A: For HE between 0.625 and 1um and HE1 past .755um,
the window transmits too much and the absorption drops by
~10%. Because of this, the thermal heat sink compound behind
the absorber can dry out. If the power and energy is kept
to 1/10 of maximum and the calibration is not important,
the sensor can be used in this spectral region.
A: Yes. To do so, the smart plug should be attached
to the Ophir smart sensor to BNC interface (Ophir P/N 1Z11010)
and the output should be put into an amplifier with input
impedance set to ~10KOhm.
A: Thermal sensors for intermittent use such as models
30(150)A, L40(150)A etc. can be used up to the powers in
parenthesis for a period given approximately by the following
formula: The rule of thumb is that you can use the sensor
for 1 minute/watt/cm3 of sensor. So for 150 watts for 30(150)A
you have 1minute*165cm3/150watt =~ a little over one minute.
The sensor finder program calculates the allowability of intermittent
use when the user fills out the choice for duty cycle.
A: It is flat for <750nm and for >900nm but can vary
+/-2-3% between those regions. Since it can vary in either
direction, this information cannot be put in the spectral
graph.
A: Water cooled sensors will not work properly at all
unless the sensor is filled with water to make thermal contact
between the disc and sensor. If the sensor is filled with water
and the input and output connectors are stopped up, then
the sensor can be used for a short time without water flow
or at much reduced power continuously. Note, however, that when used this way, the response time of the sensor may not be optimal and it may be slow or overshoot.
A: Water cooled sensors will hardly be affected by ambient temperature since the sensor temperature is determined by the water temperature. Ophir convection and fan cooled sensors are designed to operate in an ambient environment of 25degC up to the maximum rated power continuously. At this power, the sensors should not exceed about 75degC in temperature. If the room temperature is higher, then the maximum power should be derated accordingly. For example if the room temperature is 35degC, then the maximum power should be (75-35)/(75-25) = 80% of maximum rated power.
A: Surface Absorbers are spectrally broadband and spectrally flat due to their absorbing surface. With Surface Absorbers, the photons are converted to heat in the front layer of the absorbing surface.
The P versions of these sensors have a ground glass absorber. This provides superior damage resistance for high energy Q-switched type lasers, but has a low damage threshold for CW lasers. This type of sensor is referred to as a Volume Absorber; the laser energy is absorbed in the volume of the material below the front surface.
For a detailed discussion of thermal surface and volume absorbing sensors and absorbers for high power lasers, click here.
A:
In normal (CW) operation, the CCD is automatically triggered
to start a measurement. At the end of the integration time,
the voltage for each pixel is read out of the CCD serially
and converted by the A-to-D into a 12-bit digital value
When the PLD has finished reading all the pixels of the
CCD it signals to the PC that data is ready to be read.
After the PC has finished reading the data, the next available
measurement of the CCD is again stored and the cycle continues.
In Pulsed Mode for Long Pulses ( >5µs ), the CCD is triggered
by the trigger circuit instead of automatically as for CW
mode. As the pulses are long, their intensity can be read
by the CCD after it is triggered, by setting the appropriate
shutter time for the length of pulses.
In Pulsed Mode for Short Pulses ( <5µs ), the same method
as for long pulses cannot be used because once the circuit
is triggered, the pulse has already finished. Therefore,
the CCD is triggered automatically as with the CW mode,
but after each measurement of the CCD, the PLD checks to
see whether the trigger circuit received a pulse while the
CCD was measuring. If so, the data is and the cycle continues
as normal; otherwise a new CCD measurement is made.
In most cases of pulsed light sources, CW operation will
be sufficient (and the intensity can be adjusted by adding
filters or reducing the Shutter Time). In that case, the
Shutter Time should be adjusted to capture a few pulses
of light for each CCD integration, to avoid having 'empty'
measurement cycles where no light is captured by the CCD.
In the case that the pulses are slow, and/or the Shutter
Time would have to be excessively long to guarantee capturing
at least one pulse each time, the Pulse Mode operation can
be used instead.
A:
What determines this is the amount of power getting through
the slit of size 5µm x 3mm so as long as the light source
is larger than 3mm to overfill the slit, the power density
is what determines this.
At a typical wavelength of 670nm, the reading reaches full
scale where the exposure time x power density ~ 2E-7 Watts
* sec / cm2.
Since the longest exposure time is 7s, and we can easily
read 1/100th of full scale, the lowest power density on
the slit will be ~ 0.5nW/cm2. If the input is from a fiber,
you can use the SMA fiber input accessory (Ophir P/N 1Z08205)
with focusing lens (Ophir P/N 1G01236) to focus the fiber
output onto the slit.
Since the shortest exposure time is 28µs, the highest power
density we can read is ~ 1mW/cm2. In practice, we can always
spread the beam as much as we want or reflect it off of
a diffusing surface into the WaveStar so there is really
no limit to how high a power we can measure.
A:
For 905nm the single shot energy threshold is ~ 100nJ/cm2
falling on the input slit of 5um x 3mm. At 1030 - 1100nm
the sensitivity will probably be 10 to 100 times less.
A:
In response to growing customer demand, WaveStar is being
upgraded to include ActiveX controls. This will allow other
applications (such as LabVIEW, LabWindows, Visual Basic,
Visual C++) to control WaveStar parameters and collect measurements
in real time. This will be included in the next release
of WaveStar (February 2002).
A:
When the power calibration of the WaveStar is activated
by pressing the P icon, the software puts in a calibration
factor for each wavelength which compensates for the variations
in sensitivity of the WaveStar at various wavelengths and
produces a spectral curve which has the correct relative
intensity values. For instance, if the light at one wavelength
has twice the intensity of another, the display will show
a relative height difference between the two wavelengths
of a factor of 2.
The correction curve is generated by exposing the WaveStar
to a NIST traceable calibrated wide band light source. The
software compares the known relative intensity values of
the lamp spectral curve with the values produced by the
WaveStar and generates a correction curve.
A:
You absolutely can use the Quasar to do data collection, but how similar the process will be depends on the type of sensor being used. If you are using Ophir Thermopile and Photodiode sensors, these work much the same way on the Quasar as they do on the Nova-II. You should be able to collect data in much the same way as you do today. You just need to establish a Bluetooth connection, open a COM port on the PC, and then can send commands as with the Nova II. You might need a small amount of low level code just to send/receive the commands and strip the prefix/suffix, which is not difficult. Ophir-Spiricon tech support can help. If you are using Pyroelectric sensors, however, you will have to wait for the ActiveX package to be released, because the communications are very different from the Nova II, and you will not be able to handle the data on your own. Your data collection software might be somewhat different, as well, but it will function similarly to the Pulsar. ActiveX for the Quasar is tentatively scheduled for the beginning of 2009. Note also the "every pulse" data rate on the Quasar with a Pyro sensor will be lower than on the Nova II; we guarantee 500 pulses/second in our spec.
A:
The Quasar is no different than the other instruments that have electronic components: it requires annual recalibration. But it’s up to the customer whether to do this or not. We know that the calibration of the instruments degrades somewhat over time, as shown in the datasheet. This may or may not affect your particular application. To maintain compliance with ISO and other standards, we highly encourage annual recalibration.
A:
Unfortunately, this is not possible, at this point. The Quasar can establish a connection with only one host PC at a time. If you connect to the laptop in the clean room, you will not be able to then connect to another PC in an adjacent office; the Quasar will be locked out. You would have to cut the connection on the laptop before you could establish the connection to the second PC. On the other hand, the beauty of the Quasar is that you can ONLY connect to the second PC in the adjacent room, outside the clean room, and log all the data from there. There is no need for a laptop in the clean room, unless of course, if you need to observe data while in there, in which case you would have to do the above.
A:
In actual testing done at customer sites, using the high power option, there was not a place within 100 meters that we could not connect, including going through multiple walls that were made of drywall. The only time we lost transmission was when the walls were made of concrete or we had to pass through some metal doors. With normal labs and offices the signal went right through. In several cases, including a solar power scribing application where windowed doors had to be closed, we were getting a continuous connection as we walked around the spacious building into offices and labs. With the standard range option, the range should be about 1/3 of this i.e. 30 meters.
A:
Quasar runs on Bluetooth, the 2.4-2.5GHz "ISM" band (ISM = Industrial, Scientific and Medical). This is the same band used by WiFi and other technologies. This frequency was chosen as it is available without restrictions around the world. Because other technologies also use it, Bluetooth has to be designed to tolerate interference from other sources. It does this by swapping between 79 channels, at 2.402GHz up to 2.480GHz (each channel is 1MHz). This type of modulation is called FHSS, Frequency Hopping Spread Spectrum. If data does not get through on one channel it retries on a different channel. Other technologies, such as WiFi, use different techniques.
This design makes Bluetooth very robust. In principle, if there is another radio transmitter nearby that is using the same 2.4-2.5GHz band AND using the same modulation scheme, interference is a possibility, but not a real likelihood. If the other transmitter is using a different band, there should not be a problem, because there is very little interference produced at other higher or lower frequencies - this is checked during qualification of these devices for CE and FCC in RF test labs.
In general, Bluetooth is in common use everywhere, by cellular phone headsets, for example, so interference is not normally a significant risk factor.
