Your Files on a PC — Exactus Helios

Connect

Connect the device to your computer

Before you start

The device, switched on.
The USB-C cable supplied with the device.
A computer running Windows or macOS.

Switch the device on.
Connect the USB-C cable to the port on the bottom of the device, and the other end to your computer.
On the device, tap the cogwheel button in the bottom-left corner of the measuring screen. The Settings screen opens.
Tap the tile named “Connect PC”. The Connect PC screen opens, titled “Connect to PC”.
Tap “Connect”. The button reads “Connecting...” for a moment. The title then changes to “Connected to PC”.
On your computer, open the new drive. It is named HELIOS if the card in the device was formatted by the device itself. A card formatted anywhere else keeps the name it already had.

While the device is connected, the screen stays on “Connected to PC”. You cannot measure or move to another screen until you disconnect. The “Connect” button does nothing until a cable is plugged in.

Figure 1 — The Connect PC screen before you connect, and while the drive is open on your computer. The warning mark on the second screen means the cable is live: do not pull it.

The drive

What you see on the drive

The drive is the memory card inside the device. Everything the Helios saves is here. Four things on it matter to you.

HELIOS

records Folder Your data
Records.csv File
locations.csv File Edit this
app.log File

Figure 2 — What the drive looks like when it opens. Your computer may show these in a different order.

records — a folder. Every measurement you save is in here.
Records.csv — a file. One line for every measurement on the device.
locations.csv — a file. Your list of places. This is the one file you are meant to edit.
app.log — a file. The device’s own service log. You do not need it. Once it passes 5 MB the device starts a new one and keeps up to five older copies, named app.1.log to app.5.log.

A firmware file you copy across sits here too, and disappears by itself after the update runs. The device also writes a few hidden files that Windows and macOS do not show by default. Leave those alone.

Caution: copy files off the drive rather than moving them, and do not rename or delete anything you did not put there yourself. The full list is under What not to rename or delete, below.

Records

Inside the Records folder

Every measurement you save becomes one folder inside records. The folders are sorted by date: a folder for each month, then a folder for each day, then one folder per measurement named by the time it was taken. A measurement started at 14:22:07 on 5 September 2026 lands in records/2026-09/05/142207. The times are the device’s own clock, so set the clock before you start.

HELIOS/records/2026-09/05

091544 Folder
142207 Folder One measurement
142441 Folder
143102 Folder

HELIOS/records/2026-09/05/142207

20260905-142207.json File
20260905-142207_first.jpg File
20260905-142207_last.jpg File
20260905-142207_min.jpg File
20260905-142207_max.jpg File
20260905-142207_avg.jpg File

Figure 3 — One day of measurements on the left, and one measurement opened on the right. Every measurement holds one data file and up to five pictures.

What one measurement contains

20260905-142207.json — the full detail of the measurement, in a format a program can read. It holds the device serial number, the firmware version, the location, the emissivity, the mode, the unit, the date, the summary values, and every temperature sample taken during the pull.
20260905-142207_first.jpg — the first moment of the measurement.
20260905-142207_last.jpg — the last moment. This is the temperature shown on screen when you release the trigger.
20260905-142207_min.jpg — the coldest moment.
20260905-142207_max.jpg — the hottest moment.
20260905-142207_avg.jpg — the moment nearest the average. The device does not show this one on its own screen. It is on the drive for you.

The pictures are 240 × 400 pixel JPEGs from the camera, with the aiming mark and the reading drawn over them. A short pull can produce fewer than five: one moment can be the first, the hottest and the coldest at the same time, and then only one picture is kept. Five is the most you will ever see, not the usual number.

The device shows the same measurements on its own Records screen.

If you have not saved any measurements yet, this folder is empty. That is normal.

Summary

Every measurement in one file

Records.csv holds one line for every measurement on the device. It is a plain text file. Open it in a spreadsheet program such as Excel, or in any text editor.

HELIOS/Records.csv

Time Stamp	Tag	Sub Tag	Emissivity	Mode	Unit	Measured Value	Min Value	Max Value
2026-09-05 14:22:07	Reformer 1	Tube 12	0.95	Average	C	812	798	830
2026-09-05 14:24:41	Reformer 1	Tube 13	0.95	Average	C	806	791	819

Figure 4 — The first rows of the summary file. Scroll it sideways to see every column, or read the full list below.

The nine columns of Records.csv, in the order they appear.
Time Stamp	The date and time the measurement was taken, as `YYYY-MM-DD HH:MM:SS` on the device clock.
Tag	The location you selected. Empty if you selected none.
Sub Tag	The sublocation you selected. Empty if you selected none.
Emissivity	The emissivity used for the reading, to two decimal places.
Mode	The measurement mode: `Instant`, `Average`, `Max` or `Min`.
Unit	`C` for Celsius or `F` for Fahrenheit. This is the unit the three temperatures on the same line are written in.
Measured Value	The final reading, in whole degrees.
Min Value	The lowest temperature seen during the pull, in whole degrees.
Max Value	The highest temperature seen during the pull, in whole degrees.

Temperatures in this file are saved in the unit set on the device at the time. Check the unit before you compare files taken on different days.

Deleting a record on the device also removes its line from this file. Deleting a measurement folder from your computer does not: the line stays, and the file then lists a measurement whose folder is gone.

Locations

Edit your list of locations

The Helios can tag each measurement with the place it was taken. You build that list yourself, in a text file on the drive. The device ships with three example lines so you can see the shape.

Open locations.csv on the drive, in a text editor. On Windows use Notepad; on a Mac use TextEdit.
Replace the example lines with your own places.
Save the file. Keep the same name, and save it as plain text.
Disconnect the device, as described below.
On the device, open the Location screen. Your places are there.

HELIOS/locations.csv — as shipped

# locations.csv - your location list for this device.
# One line per parent location. First field = parent; the rest = its sublocations.
# Separate fields with commas. Do NOT put a comma inside a name.
# Lines starting with # are comments and are ignored.
# Edit the rows below or add your own then save. Delete these sample rows when done.
# To load changes: copy this file over USB then disconnect - or use Settings > Reload locations.
Location 1,Sublocation 1-1,Sublocation 1-2,Sublocation 1-3
Location 2,Sublocation 2-1,Sublocation 2-2,Sublocation 2-3
Location 3,Sublocation 3-1,Sublocation 3-2,Sublocation 3-3

HELIOS/locations.csv — after your edit

# locations.csv - your location list for this device.
# One line per parent location. First field = parent; the rest = its sublocations.
# Separate fields with commas. Do NOT put a comma inside a name.
# Lines starting with # are comments and are ignored.
Kiln 2,Inlet,Burner 1,Zone A
Furnace area 3,Inlet,Burner 1,Burner 2
Cooling bay 12,Zone A,Zone B

Figure 5 — The locations file as the device ships it, and the same file after an edit. Keep the file name and the layout; change only the names. The comment lines are long, so each pane scrolls sideways.

Caution: the file as shipped ends its comments with a line offering “Settings > Reload locations”. That control does not exist on this firmware. Disconnect the device, or restart it, as described below. Nothing else loads your edit.

How to write the file

One line per place. The first name on the line is the place; every name after it is a part of that place.
Separate the names with commas.
Do not put a comma inside a name. There is no way to escape one.
A line that starts with # is a comment and is ignored. So is an empty line.
Keep each name to 60 characters or fewer. A longer name is cut short on the device.
Use plain Latin letters, digits and normal punctuation. Chinese, Japanese and Korean characters are shown as question marks on this firmware.
Save as plain text. The device accepts either Windows or Mac line endings, and tolerates spaces around a name.
You can have up to 256 places, each with up to 128 parts. If you write the same place name twice, the two lines are merged into one.

The device reads this file again each time you disconnect, so there is nothing else to press. Restarting the device also reads it. If a name is too long the device shortens it; if a character cannot be shown it becomes a question mark. If the file is larger than 256 KB the device loads no locations at all. If the file is missing, the device writes a fresh copy of the example file at the next start, and your own list is gone. Keep a copy of your edited file on your computer once you are happy with it: that copy is the only one that survives a Factory Reset, described under What not to rename or delete.

Care

What not to rename or delete

Do not rename a measurement folder. Four parts of the device work out where a measurement lives from its name. Rename one and the device looks in the wrong place, without saying so: the pictures come up blank on the Data point screen and the device cannot tidy the folder away later.
Do not delete or rename the hidden file .recycle_db inside records. It is the device’s index of what it has saved. Without it the device loses track of every measurement already on the card, and stops tidying them away. Nothing on screen tells you this has happened.
Do not rename Records.csv or locations.csv. The device looks for those exact names, with that exact capital letter on Records.csv.
app.log and its numbered copies are safe to delete. The device starts a new one when it next switches on. They are the largest thing on a lightly used card.

Caution: if locations.csv is missing, the device writes a fresh copy of the example file at the next start, and your own list of places is gone. If Records.csv is missing, the device starts a new one at the next measurement, and every earlier line is gone. Neither can be recovered from the device.

Caution: Factory Reset, under Settings then Format / Reset, erases everything on the Helios drive — your measurements, Records.csv, your locations file, the log file and any firmware file you have copied over — and returns every device setting to its factory value. The warning on the device screen says only that it removes custom configurations. It does more than that, and it cannot be undone, so copy anything you want to keep to your PC first.

Caution: your locations.csv is deleted along with everything else, and the device writes a fresh sample file in its place at the next start-up, so any locations you added are gone — keep a copy of the file on your PC before you reset. Nothing on the device warns you about this.

Format USB Drive, on the same screen, is a second destructive control and does something different: it erases all files on the drive and gives it a clean filesystem named HELIOS, and your device settings are kept. Factory Reset deletes the drive’s visible files and your settings and leaves the filesystem alone. Format USB Drive restarts the app on the device; only Factory Reset restarts the device itself.

How much the device keeps

The device keeps the last 500 measurements. When you save the 501st, it deletes the oldest one to make room. It does that quietly: there is no warning and nothing on screen changes.

There is no check on free space either. The device does not tell you the card is filling up and does not stop when it is full. Records.csv and app.log sit outside the 500 limit and keep growing on their own, so the summary file can list measurements whose folders the device has already removed.

If your measurements matter, copy the records folder and Records.csv onto your computer regularly. The device is not a place to store them long term.

Disconnect

Disconnect safely

Close any file you opened from the drive.
On your computer, eject the drive. On Windows, right-click the drive and choose Eject. On a Mac, click the eject symbol next to the drive in Finder.
On the device, tap “Disconnect”. The button reads “Disconnecting...” for a moment, then the title changes to “Disconnected”. If ejecting on the computer already released the drive, the device may go back to “Connect to PC” on its own before you tap anything. Either screen means the drive is released.
Tap “Done” if the device is showing “Disconnected”, then unplug the cable.

Figure 6 — The screen the device shows after you tap “Disconnect”.

Caution: always eject on the computer and tap “Disconnect” on the device before you unplug the cable. Pulling the cable while a file is still being copied can damage the files on the drive.

Caution: pulling the cable also leaves the device stuck. The Helios only lets go of the memory card when you tap “Disconnect”. Unplug without tapping it and the card stays handed over to a computer that is no longer there: the trigger does nothing, and no measurement is saved. Nothing on screen explains this. To recover, plug the cable back in and tap “Disconnect”, or switch the device off and on again.