HLP-200B CO₂ Laser Power Meter

What with Christmas approaching, I got myself an HLP-200B CO₂ Laser Power Meter:

It’s a hefty chunk of aluminum, as befits a device intended to soak up a 200 W CO₂ laser beam, and both sides have a relentless simplicity:

Having not found an online version of the manual:

You’re welcome.

[Edit: A slightly different version of the manual is online at https://www.ccbluetimes.net/pages/support ]

The manual does not exactly match the hardware. In particular, “so users won’t need any tools to replace the battery” is incorrect:

Until you loosen the M2 setscrew below the finger notch a couple of turns, “Use just fingers to remove the battery cover” will merely scuff your fingerprints. Apply a 1.5 mm or 1/16 inch straight screwdriver bit with no more than finger torque and, after two or three turns, the lid comes free.

The meter arrives without a battery, so you passed the first test.

Despite the “another screw hold (M4) is added”, there’s only one tapped hole in the case, as visible in the back panel photo. Seen from the front, it’s above the four digit LCD.

Operation is at best awkward and at worst hazardous:

• Press the blue button to turn it on and hear a beep
• It’s ready to measure within three seconds
• Hit it with the laser beam until it beeps
• The LCD shows the power for six seconds
• It shuts off with a beep
• Bonus: If the meter doesn’t detect any energy, it shuts off 20-ish seconds after the button press

Minus my power ears, the beeps are completely inaudible.

The meter is sensitive enough to respond to weak heat sources like LED bulbs and even fingertips, so you can test it without firing the laser. The numeric value shows the power from a CO₂ laser beam dumping an equivalent amount of energy into the sensor:

The sensor target is 20 mm OD, although the instructions remind you to “Ensure the laser is emitted to the center of the sensor”. I suspect hitting the sensor with a focused laser spot will eventually damage the surface.

Making a real measurement requires:

• Set the Pulse button for continuous output
• Set the power level
• Defeat the lid interlock switch on the laser cabinet
• Push the blue button on the HLP-200B
• Quickly position the meter target accurately in the beam path
• Hold down the laser Pulse button
• Freeze in that position until the meter beeps
• Release the Pulse button
• Quickly reorient the meter and read the display

I have a visceral reluctance concerning safety interlock overrides, misgivings about poking my head inside the cabinet, and no yearning to put one hand near the beam line with the other on the console. Yes, I have known-good laser safety glasses.

The meter generates plausible results for the (claimed) 60 W tube in my machine, but further tests await conjuring fixtures to keep various irreplaceable body parts out of harm’s way.