This discussion has been locked.

You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Altimeter Fenix 5

This morning, as I always do, I drove 22 miles to work in the North west of England. According to several websites there is a difference in altitude between my start and finish points of circa 220 feet, the altimeter on my Fenix 5 shows no difference in altitude at any time in the last 4 hours. Is there a setting that I have wrong or is it a faulty unit?

I've had the watch less than a week so haven't noticed this before, so I don't know if this is the first occasion or whether or not the unit has been showing different altitudes previously.

Any assistance would be really appreciated.

0 AllanOlesen67 over 7 years ago

I set up a screen with height, pressure and temperature

Which pressure? The watch has both an Ambient Pressure and a Barometric Pressure.

0 tgregers over 7 years ago

Which pressure? The watch has both an Ambient Pressure and a Barometric Pressure.

Barometric pressure steady, ambient changing.
Now I've tried out the SW 7.02beta, and also 7.10beta (which came out yesterday). None of them solved the problem :(

0 Former Member over 7 years ago

I set up a screen with height, pressure and temperature (I think the pressure will vary if the temperature changes). Temperature shows steady while both pressure and height change. So then it is a software error, which will explain why the watch worked until I paired with the hart rate sensor. I off course tried to both turn the external sensor off and unpair it, but that didn’t help.

Hi -
I have the same problem. Yesterday, after calibrating the altimeter and setting the pressure widget, I had thousands of feet climbed and -ve. Could you explain in layman's terms how I check if it is a software error or a sensor error please.
This is my second F5, and it gets somewhat annoying setting up the watch to your liking and having to send it back!!!

Thanks in advance

0 AllanOlesen67 over 7 years ago

Could you explain in layman's terms how I check if it is a software error or a sensor error please.

You have to look at Ambient Pressure (do not use Barometric Pressure!) which is only available as a data field in activity screens. When you don't move around, and you don't stay at a place where ventilation etc. can change the air pressure, ambient pressure will change slowly over time, depending on the weather. The change over time should behave like this:
- Changes will be slow, not more than 1-2 millibar within an hour. (2 millibars would be a quite violent weather change).
- The ambient pressure should not change with more than a few tenths of a millibar if you cool or heat the watch.
- If you are at sea level, the ambient pressure will usually be between 980 and 1040 millibar.
- If you are at a higher altitude, the ambient pressure will be lower. In my area, it drops 1 millibar for each 8-9 meter.
- The changes in ambient pressure should follow the weather stations in your area, albeit with a fixed offset if you and the weather station are at different altitudes, or the weather stations reports the equivalent pressure at sea level.

If the ambient pressure does not behave as this, you have a sensor issue. Either the sensor has a defect, or you have blocked the sensor's vent hole.

In the latter case, I assume that you will see the ambient pressure changing a lot if you heat or cool the watch. (If you trap air inside a space and heat it or cool it 10 °C from room temperature, you will get an approximate 3% pressure change which would be equal to 30 millibar at sea level).

The reason that it is important to use Ambient Pressure and not Barometric Pressure is that Barometric Pressure is an artificial value, calculated from the measured ambient pressure and an assumed altitude (Barometric Pressure is supposed to be the equivalent air pressure at mean sea level). So if you don't have the correct altitude displayed on the watch, you will not have the correct Barometric Pressure displayed either, even if the measured ambient pressure is correct.

(If you use other pressure or altitude units than millibar and meter, I will be happy to change the values in the explanation above. Millibar and meters just happen to be my units.)

0 tgregers over 7 years ago

I still don't quite understand what goes on with my Fenix 5 with regards to the pressure/altimeter function. It's really frustrating, because I love the watch but with respect to the altimeter function it’s rubbish.This morning at 08:30 I calibrated it to show the same (1016mb) as an external electronic barometer I got.

So the watch then showed:
Ambient pressure, Barometric pressure, altitude, temp
998.1 1016 105 28.9

At 10 o’clock I went for a 11k run, and the watch really behaved. It was only 6m of when I came home, which I find acceptable as it was quite cold (-10C) and a bit miscalculation with such temperature differences is ok. I’ve seen that with all other sports watches I’ve had.

But now at 16:30 it has started running the altimeter again. Now it shows (for about a second. It counts between 1 and 20 meters altimeter change pr second…):
Ambient pressure, Barometric pressure, altitude, temp
862.1 1015 1303 28.8

The external barometer now shows 1015 so it has got that one right.

It really does quite opposit of what AllanOlesen67 say. It calculates the barometric pressure correct but the altimeter and ambient pressure is wrong. Could it still be a software issue? If so, there might be a hope that Garmin will fix this? If not perhaps I should stick to my Fenix 3 which doesn't have any altimeter problems and return the Fenix 5.

0 Former Member over 7 years ago

You have to look at Ambient Pressure (do not use Barometric Pressure!) which is only available as a data field in activity screens. When you don't move around, and you don't stay at a place where ventilation etc. can change the air pressure, ambient pressure will change slowly over time, depending on the weather. The change over time should behave like this:
- Changes will be slow, not more than 1-2 millibar within an hour. (2 millibars would be a quite violent weather change).
- The ambient pressure should not change with more than a few tenths of a millibar if you cool or heat the watch.
- If you are at sea level, the ambient pressure will usually be between 980 and 1040 millibar.
- If you are at a higher altitude, the ambient pressure will be lower. In my area, it drops 1 millibar for each 8-9 meter.
- The changes in ambient pressure should follow the weather stations in your area, albeit with a fixed offset if you and the weather station are at different altitudes, or the weather stations reports the equivalent pressure at sea level.

If the ambient pressure does not behave as this, you have a sensor issue. Either the sensor has a defect, or you have blocked the sensor's vent hole.

In the latter case, I assume that you will see the ambient pressure changing a lot if you heat or cool the watch. (If you trap air inside a space and heat it or cool it 10 °C from room temperature, you will get an approximate 3% pressure change which would be equal to 30 millibar at sea level).

The reason that it is important to use Ambient Pressure and not Barometric Pressure is that Barometric Pressure is an artificial value, calculated from the measured ambient pressure and an assumed altitude (Barometric Pressure is supposed to be the equivalent air pressure at mean sea level). So if you don't have the correct altitude displayed on the watch, you will not have the correct Barometric Pressure displayed either, even if the measured ambient pressure is correct.

(If you use other pressure or altitude units than millibar and meter, I will be happy to change the values in the explanation above. Millibar and meters just happen to be my units.)

Thanks!!!

0 AllanOlesen67 over 7 years ago

It really does quite opposit of what AllanOlesen67 say. It calculates the barometric pressure correct but the altimeter and ambient pressure is wrong.

This is not opposite of what I say.

The reason that your barometric pressure is correct is that it is an artificial value which is decided by the watch. When the ambient pressure measurement decided to go off, the watch decided to stick to the last known barometric pressure. But the relationship between ambient pressure, altitude and barometric pressure has to be respected, so the watch also decided to change the altitude to something wildly off.

The problem is your pressure sensor. It is defective. Or the air opening into the sensor is blocked. You should never, ever measure 862 millibar if you are only 100 meter above sea level.

0 tgregers over 7 years ago

This is not opposite of what I say.

The reason that your barometric pressure is correct is that it is an artificial value which is decided by the watch. When the ambient pressure measurement decided to go off, the watch decided to stick to the last known barometric pressure. But the relationship between ambient pressure, altitude and barometric pressure has to be respected, so the watch also decided to change the altitude to something wildly off.

The problem is your pressure sensor. It is defective. Or the air opening into the sensor is blocked. You should never, ever measure 862 millibar if you are only 100 meter above sea level.

Oh! very sorry for misinterpreting you. I think I just don't understand how the watch manage to keep the right barometric pressure when the ambient pressure keeps wandering of. I guess I’ll be returning it then (I've checked that the air opening is not blocked). Incredible annoying :(. This is the second one I have with a faulty sensor. Maybe I’ll just keep my Fenix 3 and stay with that one.

0 AllanOlesen67 over 7 years ago

I think I just don't understand how the watch manage to keep the right barometric pressure when the ambient pressure keeps wandering of.

It is simple: The watch guesses that the barometric pressure hasn't changed. It is a simple guess, nothing else. There is no measurement of barometric pressure in the watch (and there can't be). But unfortunately, people rely too much on this guess when they try to figure out what the watch is doing.

0 wahnamch over 7 years ago

Also having issue of altimeter showing shifts of up to -12000m. Only started about a week ago (after a long-haul flight). Continues despite recalibrating a couple of times. Hope this will be resolved with the next SW release......