www.brultech.com

Looking at the following page it appears that the value should be 4k7 (whatever that is).

That would be 4.7 kilo ohms or 4700 ohms . . . That picture doesn't really help you because its based on a 3 wire Dallas 1 wire sensor. You stated you have only 2 wires so I'm not quite sure how that is supposed to work.

Can you offer a photo of one of the sensors and the make and model?

4.7K ohm resistor between Data and +5VDC. I plugged the resistor into the GEM's 1 wire connection block along with the 1 wire circuit.

https://www.ebay.com/itm/10-pcs-4-7K-oh ... SwbiFZXtUX

Here is the drawings from the DS18B20 user documentation.
Note the 4.7K resistor is close to the Bus Master.

http://www.how-to-doit.com/wp-content/u ... iagram.jpg

That's still based on 3 wires the OP says he only has 2. Whether that means there are three but is using only two who knows. I've never seen a 2 Wire Dallas / Maxim sensor before not even in chip form which has three leads for power, ground, data.


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The DS18 only uses 2 wires in figure 6.

The DS 18's +5 Volt leg is shorted to its GRD leg, and connected to the 3 wire ckt GRD wire. The DS18 DATA leg is connected to the 3 wire ckts DATA wire. The 4.7 deeds to be at the Bus Master's end of the 3 wire ckt. The 5Volt supply is not connected to the DS18. It uses the power from the data wire to charge a capacitor to power the chip.

One last thing, if you accidently hooked up the DS18 incorrectly, the chip may have been rendered useless.

It looks like you guys covered most of it.

If you're not running COM F/W V4.33 on your GEM, this is one of the instances where it might help. Paul adjusted the timing of the temperature sensors to be more to spec. You can also try dropping to COM F/W V4.22 as a last ditch effort.

COM F/W can be found here:

https://www.brultech.com/software/files/getsoft/3/1