1-wire temp always showing 128.0C

[seanwg]

Hi,

So I've hooked up a DS18B20 1-wire temp sensor to my GEM, scanned... found it ok, setup for C.

Sometimes it reports the correct temperature, but more often than not, its reporting 128.0C.

Any idea why?

Sean

[Teken]

Hi,

So I've hooked up a DS18B20 1-wire temp sensor to my GEM, scanned... found it ok, setup for C.

Sometimes it reports the correct temperature, but more often than not, its reporting 128.0C.

Any idea why?

Sean

Hello Sean,

What firmware are you on for COM / Engine for the GEM? You should be using the latest COM 3.18, Engine 1.49 as it resolved many small bugs while introducing some key features.

[seanwg]

I just upgraded...

I'm on those versions

Sean

[Teken]

I just upgraded...

I'm on those versions

Sean

Hello Sean,

Good to hear please do report back how the GEM reports back the 1 wire temps. How are you reading these temperature values?

In the GEM's live view or through SEG, Dash Box, Other? Please note you should ensure the connection is solid and the sensor(s) be placed away from any electrical wiring, and if your 1 wire sensor is like mine where it has a encapsulated SS head.

Don't let it touch any metal or other EMI device.

[ben]

Sounds like it's failing to read on occasion. I would try adding a strong pull-up resistor between 5V and Data.

[ben]

If you're technical, this link here: http://www.maximintegrated.com/en/app-n ... mvp/id/148 on long distance 1-wire networks may help.

[seanwg]

So I have the sensor, on a little say 10 cm wire out from the GEM...

Would I need a pullup on that?

Sean

[Teken]

So I have the sensor, on a little say 10 cm wire out from the GEM...

Would I need a pullup on that?

Sean

Hello Sean,

How many of these sensors do you have in place now? I ask because some of the cheaper 1 wire sensors can cause some real headaches with random values or even locking up the GEM. I would try the pull up resistor and report back how it reacts.

Since upgrading the firmware are you still seeing these values and where do you see them?

[seanwg]

Just 1 sensor right now.

Sensor is direct from digikey.

I might try running on an arduino... I have some friends who used these, and they never saw any problems



Sean

[Teken]

Just 1 sensor right now.

Sensor is direct from digikey.

I might try running on an arduino... I have some friends who used these, and they never saw any problems



Sean

Are you still seeing this elevated value right now? What method do you use to see these values?