First version
Rev 1.00
22 Sep 2016
Helios User Manual
4
Chapter 1 – Helios Operating Principle
Overview
The Helios sensor measures high power industrial lasers by measuring the energy of a short time exposure of the CW
laser. The laser should be set to pulse from 0.1 to several seconds. The Helios measures the energy and exposure time
of this sample of the power, and from this calculates the CW power.
The Helios can measure power up to 12 kW and energy to 10 kJ. The short exposure time enables power
measurement by a small sensor without water cooling (see the table in Chapter 2 for recommended exposure times by
power level).
The Helios can be operated via RS232 using a PC Application supplied with the sensor, or via RS232 user commands.
In addition, two industrial Ethernet protocols are supported:
•
Helios-Profinet (P/N 7Z02768/7Z01700) supplied with RJ45 Profinet connector (P/N 7E01298)
•
Helios-EtherNet/IP (P/N 7Z02789/7Z07101) supplied with RJ45 EtherNet/IP connector (P/N 7E01299).
Both are also supplied with the Ophir Power Cable for Helios (P/N 7Z10458A)
Other protocols may be available in the future, contact Ophir for more information.
Physical Principle
The core of Helios is a high power copper thermopile disk that can measure short exposures of very high power lasers.
The response time is 2-3 seconds so only energy of single-shots can be measured at such short exposure times.
An internal, uncalibrated photodiode detects the backscattered light to measure the exposure time.
Average power is then calculated by,
𝑃 =
𝐸
∆𝑡
,
where
P
is power,
E
is energy, and
Δt
is the time interval.
All this allows short measurements of multi-kW lasers in a small, uncooled body.
Example of Use: Laser Welder in a Robotic Cell
A typical application of the Helios is to check the power of a laser welder in between welds. This process can be
automated and optimized to take the least time away from production possible.
Here’s a typical sequence of events:
1.
Welding production “Item A” is almost done
2.
Open Helios cover and check sensor is “Ready”
3.
Finish welding production “Item A”
4.
Turn off laser
5.
Move laser to Helios
6.
Turn on laser for preset amount of time (0.1-10 s)
7.
Move laser back to production
8.
Start welding production “Item B”
9.
Read measurement (~3 seconds after laser measurement)