The key to Helios Pro’s ability to handle high powers with a small, uncooled body is the limit on exposure time. The specifications state a maximum “pulse” energy (i.e. energy during one exposure measurement) of 5kJ, so one can hit the Helios Pro with 12 kW (max power) for up to about 0.4 s for 1 measurement.

This is limited by the temperature the Helios Pro body reaches, that is measured by an internal sensor. The temperature shouldn’t be allowed to exceed 60° C. In our experience, this translates to about 30 kJ of accumulated exposure. Of course, the longer one waits in between pulses (allowing the body to cool), the more total energy it can take. That is why the temperature sensor should be used as the primary indicator of overheating, while 30 kJ should be treated as a rule of thumb.

The 2.5s response time of the Helios Pro would indeed be problematic if it were measuring the power directly. In actuality it integrates the power received to measure the energy of the pulse. An internal photodiode is used to detect the pulse width. The power is then calculated by P = E / Δt.

Basic use with Profinet, EtherNet/IP or EtherCAT requires one power supply cable and one data cable. Using RS232 or the PC application requires one power supply cable and one RS232 cable. If you want to use the Helios Pro in a line/star topology, where it is daisy-chained with the next device in line, then you should use two power supply cables and two data cables.
Cables supplied with the Helios Pro are as follows:
Model: Profinet, EtherNet/IP, EtherCAT –

• Power Supply Cable, AIDA to flying leads termination 5m (P/N 7Z10458A)
• Data Cable, Ethernet AIDA to RJ-45 5m (P/N 7E01299)

Model: EtherNet/IP-M –

• Power Supply Cable, 7/8” to flying leads termination 2m (P/N 7E01535)
• D9F to D9M Shielded 3m RS232 Cable (P/N 7E11216A) For more detailed information, please refer to the User Manual.

After the Helios Pro reaches the maximum temperature of 60° C (approx. 30 kJ of accumulated energy), it should take about 10-20 3 minutes for it to cool back down to room temperature 3 minutes for it to cool back down to below 60° C so that it will open back up for measurements again, and about 10-20 minutes to cool back down to room temperature to enable full normal usage. These times are of course dependent on ambient conditions. Therefore, use the temperature sensor as the indication of how many pulses can be measured.

Use methanol and a tissue or clean air.

The Helios Pro does not have interlock output support. In all the various data protocols, there is a command to query the current temperature. The customer is responsible for integrating this into the measurement script and coordinating with the laser control to make sure no laser exposure will take place when the temperature is over the limit. If using the PC application, one should select: Options > Log Temperature Enable. This will show the current temperature (and log it). If the temperature goes over the limit, it will turn red.

Unless otherwise indicated, Ophir sensors and meters should be recalibrated within 18 months after initial purchase, and then once a year after that.

The short answer: Yes. Now to explain: The question comes up because of the concern that the internal fast photodiode - which measures the exposure time (“pulse width”) - might get confused at sensing the end of an individual pulse within a pulsed beam, and incorrectly think that it has now measured the exposure time and needs to divide the measured energy by that time (which would of course be wrong). The Helios Pro is a bit smarter than that though. It looks simultaneously at the outputs from the fast photodiode AND from the (much slower) thermal sensor, and if it sees that the thermal sensor’s output has not “come back down”, then it knows what looked like the “end of the pulse” from the fast photodiode’s output is not really the end of the pulse.

In theory, if a beam is completely parallel and fits within the aperture of a sensor, then it should make no difference at all what the distance is. It will be the same number of photons (ignoring absorption by the air, which is negligible except in the UV below 250nm). If, nevertheless, you do see such a distance dependence, there could be one of the following effects happening:

• If you are using a thermal type power sensor, you might actually be measuring heat from the laser itself. When very close to the laser, the thermal sensor might be “feeling” the laser’s own heat. That would not, however, continue to have an effect at more than a few cm distance unless the light source is weak and the heat source is strong.
• Beam geometry – The beam may not be parallel and may be diverging. Often, the lower intensity wings of the beam have greater divergence rate than the main portion of the beam. These may be missing the sensor's aperture as the distance increases. To check that you'd need to use a profiler, or perhaps a BeamTrack PPS (Power/Position/Size) sensor.
• If you are measuring pulse energies with a diffuser-based pyroelectric sensor: Some users find that when they start with the sensor right up close to the laser and move it away, the readings drop sharply (typically by some 6%) over the first few cm. This is likely caused by multiple reflections between the diffuser and the laser device, which at the closest distance might be causing an incorrectly high reading. You should back off from the source by at least some 5cm, more if the beam is not too divergent.

Needless to say, it’s also important to be sure to have a steady setup. A sensor held by hand could easily be moved around involuntarily, which could cause partial or complete missing of the sensor’s aperture at increasing distance, particularly for an invisible beam.

There are seven LEDs for different status/error indications. From left to right (and top to bottom), the LEDs are:

1. Power
2. COM (Green)
3. COM (Red)
4. Link (Port 1)
5. TX/RX (Port 1)
6. Link (Port 2)
7. TX/RX (Port 2)

For more detailed information, see Chapter 7 of the manual.

You can download these files from the Software / Firmware Listing page, at the lower part of the page under “Legacy Software”.

The window is replaceable without need for recalibration of the sensor. Just order the Helios Pro Window Replacement Kit (P/N 7Z08447) and follow the instructions on "Helios Pro Window Replacement Kit User Notes".