Troubleshooting: meters

Start with the exact message on the meter's card or the Reading panel. These are the ones that come up most.

The meter isn't found

Work through these in order:

1. Try another USB cable and port. Many cheap cables carry power only.
2. On the NextProbe USB Meter, check Utility → Serial is set to 115200.
3. On Windows, check the meter's CH340 port appears in Device Manager under Ports. If it doesn't, install the CH340 driver from the chip maker (WCH) and plug the meter in again.
4. Close any other program that might hold the port: other meter software, a serial terminal, or a second copy of NextProbe. A serial port can only be open in one program at a time.
5. Turn the meter off and on. The NextProbe USB Meter ignores a reset command, so a power cycle is the only reset.
6. Press Find my meter on the Instruments screen.

"Close the program that has … open and press Connect"

The message names the meter's port where the … is. Another program has that port open. Close it and press Connect. If the port stays busy, unplug the meter and plug it back in; the bench tries again by itself after 30 seconds.

"This account cannot open …. Check the port's permissions and press Connect."

Your computer account isn't allowed to open the meter's port. Ask whoever manages the computer to give your account access to the port, then press Connect.

"Plug the meter back in and press Connect. … is no longer there."

The meter went away: the cable came out, or the meter turned itself off to save its battery.

"That is not the NextProbe USB Meter. The device on this port answered …"

A different device is on the port the bench tried. Unplug other USB serial devices, or connect the right one.

"No reading from the meter for a few seconds"

The meter stopped sending. The bench is already trying to wake it. Check the cable and that the meter is on; Capture is refused until readings come back. On the NextProbe USB Meter in temperature mode, a three-second pause every ten minutes is normal.

The step wants a mode and the reading is refused

On a dial meter, the reading is refused until the dial is on the mode the step names. Turn the dial. On the NextProbe USB Meter, the bench sets the mode itself; if the meter keeps reporting another mode, power-cycle it.

The reading never settles

Auto-capture needs the meter to hold still within the tolerance for the hold time. A probe not quite on the pad wanders, and so does a rail that is oscillating. Hold the probes still, or press Capture to take the reading as it is. A handheld meter with a bouncing last digit settles better with Tolerance set to Loose in Settings → General.

"Move the probe to the point"

The meter reads what it read on the last step, so the probe probably hasn't moved. Put it on the new point. If the two points really do read the same, press Capture.

An OL reading doesn't take itself

Open readings never capture on their own. If OL is the answer, press Capture.

The reading is just off the range, tens of millivolts away, on every diode step

Diode readings differ between meters by tens of millivolts. Compare against a known-good board (Compare with a good board). Calibrating on the card won't help yet: the bench can't save a calibration until the card's reference values ship in an update (Calibrate a meter).

"The calibration card's reference values have not been measured yet, so nothing is saved"

That's expected for now, and Save calibration stays greyed out. The bench saves a calibration only once the card's reference values ship in an update. Until then it uses diode readings as the meter gives them. Everything else works normally.

There's no simulated meter on a real board

That's deliberate. The simulated meter runs only in demo mode, so it can never put a made-up reading on a real board. Connect a meter or type the readings.