A Field Measurement Checklist: FARO Products, Mini Multimeters, and Thermal Camera Phones

I've been handling industrial measurement equipment orders for about eight years. I've personally made and documented 17 significant mistakes in that time—roughly $48,000 in wasted budget. This checklist exists because I don't want you to repeat them. It's for anyone who specs, buys, or uses FARO laser trackers, portable CMM arms, mini multimeters, or thermal camera phones. Six steps. Follow them in order if you can. If you're in a hurry, skip straight to the calibration section—that's where the expensive ones hide.

What this checklist is for

This is a practical list for field measurement and maintenance troubleshooting. It covers three very different tools:

• FARO products — laser trackers, portable CMM arms, and related metrology software.
• Mini multimeters — small electrical testers for voltage, resistance, and current.
• Thermal camera phones — compact infrared imagers like the FLIR One that attach to a smartphone.

These tools don't replace each other. A FARO Arm won't tell you why a motor is overheating. A mini multimeter won't measure a 12-meter diameter. A thermal camera won't verify a machined surface. But put them together in the right order, and you can solve a lot of field problems before they become production failures.

Step 1: Define the measurement question first

When I first started managing measurement equipment, I assumed the most precise tool was always the safest choice. That's wrong. It's also expensive.

For example, if you need to check the flatness of a large machine base during installation, a FARO Laser Tracker gives you a 3D visual of the entire surface. That's the right tool. If you only need to confirm a single dimension on a part sitting in a vise, a FARO CMM Arm may be overkill—unless you also need that part's inspection report in the metrology software. The question isn't 'what's the best instrument?' It's 'what measurement decision am I making?'

Here's what most people don't realize: the instrument that answers the question is the one that gives you enough accuracy and enough traceability at the same time. A mini multimeter can tell you a battery is dead. It cannot tell you whether that dead battery caused a PLC fault. A thermal camera phone can show you a hot breaker. It cannot tell you the breaker's load current. Define the question, then choose the tool.

Step 2: Verify accuracy specs under your real conditions

Most buyers focus on the headline accuracy number and completely miss the environmental specification. That was my blind spot. I once approved a portable scanning system because the brochure said 0.1 mm. In my workshop it was 0.3 mm—because the temperature range was different, and we hadn't accounted for thermal expansion on the fixture.

What major vendors won't tell you is that 'accuracy' in a spec sheet is usually measured under controlled conditions. That doesn't mean the spec is a lie. It means you need the full statement: temperature range, measurement volume, operator skill, and calibration status.

Per FTC guidelines (ftc.gov), advertising claims must be truthful, not misleading, and substantiated. When a company claims a FARO product is accurate to a certain number, ask for the test report. Ask for the measurement uncertainty budget. If the vendor won't share it, that's a red flag.

Step 3: Match the mini multimeter to the job

The first time I ordered mini multimeters for a team of field techs, I bought on price. It was 2017, and the $8 unit seemed fine for 'simple checks.' It wasn't. The first time one of my techs measured a 24 VDC sensor circuit with a meter that had no CAT rating, the reading jumped around and then settled on a completely wrong value. That false reading led us to swap a good sensor, delay the line by a day, and then discover the real problem was a loose terminal.

That error cost $890 in rework plus a one-week delay. The $8 multimeter went in the trash.

For field work, a mini multimeter should have, at minimum:

• CAT III or CAT IV rating, depending on where you're measuring.
• AC/DC voltage, resistance, and continuity.
• Clear input protection and fused current input.
• A battery indicator that doesn't randomly go dead (ask me how I know).

Don't buy the cheapest one. Don't buy the most expensive one either. Buy the one that is certified for the electrical environment where your team works.

Step 4: Use a thermal camera phone for screening, not final answers

A thermal camera phone is brilliant for finding problems fast. In a small electrical panel, it can show you a hot connection before it fails. But a thermal image is a surface-temperature picture, not a calibrated measurement. If you need to trend temperatures over time, use a contact probe or a radiometric thermal camera with a calibration certificate.

How to use a FLIR thermal camera: a short sub-checklist

Since 'how to use a FLIR thermal camera' is one of the most common questions I get, here's the version I hand to new techs:

1. Set the emissivity first. Most FLIR camera phone apps default to 0.95. That works for tape and skin, not bare metal. For a shiny aluminum motor housing, set emissivity to ~0.30 or use electrical tape with a known emissivity.
2. Focus before you capture. An out-of-focus thermal image is useless for reporting, and the app won't fix it later.
3. Adjust the temperature span. Auto span can hide a hotspot if the scene also contains a very hot or very cold object. Narrow the span to the range you care about.
4. Take a visible-light photo at the same time. You'll need it when someone asks where exactly the hot spot was.
5. Don't shoot through glass or water. You'll get the glass temperature, not the target temperature.

The question everyone asks is 'how accurate is it?' The question they should ask is 'is the hotspot visible and reproducible?' A thermal camera phone is a screening tool. It tells you where to investigate. The multimeter tells you if it's electrical. The FARO Laser Tracker tells you if it's geometric. None of them replace the others.

Step 5: Track calibration dates for every FARO product

A FARO Laser Tracker is an impressive piece of engineering. It's also a precision instrument with a calibration interval. So is a portable CMM arm. So is a thermal camera, if you're using it for reporting. If the calibration certificate has expired, your measurement results don't have traceability. In a quality management system, that's the difference between a pass and a failed audit.

I once missed the calibration due date on a FARO CMM Arm because the arm 'looked fine.' We used it for three weeks before the annual audit. The audit found the certificate was out of date, and every measurement taken in those three weeks was suspect. That's not a small deal: it was a 3-day production delay and a very uncomfortable client meeting.

Here's the rule I now enforce:

• Every FARO product has a calibration due date entered in the maintenance calendar.
• No instrument is used beyond its calibration date without a documented risk assessment.
• Calibration is scheduled before it expires, not after.

This is also where 'value over price' matters. A calibration agreement may feel like an unnecessary cost. The alternative can be an entire batch of unusable data.

Step 6: Compare total cost, not sticker price

My rule about buying FARO products now: calculate the total cost of ownership before comparing quotes. That includes:

• Hardware cost.
• Software licenses and updates.
• Operator training.
• Calibration and maintenance.
• Accessories, cables, and transportation cases.
• Support response time.

When I compared two quotes for a FARO Laser Tracker side by side—same model, one quote was sparse on the extras, one quote included everything—I finally understood why 'cheaper' doesn't mean 'less expensive.' The seemingly lower quote didn't include the transport case, the training day, or the first calibration. By the time we added those, it was more expensive than the other quote.

The upside of choosing the cheaper quote was $2,000 on paper. The risk was having to redo a week's measurements because we didn't know how to operate the system correctly. I kept asking myself: is $2,000 worth potentially losing the client? No. We paid for training, and it saved us far more than that. (Note to self: I should have made that call in week one, not month four.)

If you cannot measure the total cost, you do not have a comparison. You have a guess.

What still goes wrong

Even with the checklist, I still see the same errors. Maybe this will save you one of them:

• Buying a mini multimeter without checking its CAT rating.
• Using a thermal camera phone without setting emissivity.
• Treating a FARO product like a tape measure and skipping the accepted measurement procedure.
• Deferring calibration to save money on a service line item.
• Buying measurement software and skipping the training on how to use it.
• Assuming the 'standard accuracy' in a brochure applies in your workshop environment.

If you take one thing from this article, take this: every measurement decision is a decision about risk. The tool is only as good as its specification, its calibration history, and the person using it. Start with the question, verify the spec, and count the total cost. The right FARO product, mini multimeter, or thermal camera phone is the one that can be trusted when it matters.