7 replies to this topic

[fctavares]

Hello! I?m starting to try the lm335az for a temperature sensor, i?ve got this information from somewere in the web does any body tryed this out? , before i lose to much time with this gadget! kind regard?s

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[LabJack Support]

The LM335 works fine with the U12. It is used in our EI-1022 probe. The schematic you found looks like the "Basic Temperature Sensor" figure from the LM335 datasheet (national.com).

http://www.labjack.c...4751273;start=1

You might also consider the LM34CAZ, which does not need a resistor:

https://forums.labja...?showtopic=1040

[lknweather]

The LM335 works fine with the U12. It is used in our EI-1022 probe. The schematic you found looks like the "Basic Temperature Sensor" figure from the LM335 datasheet (national.com).

http://www.labjack.c...4751273;start=1

You might also consider the LM34CAZ, which does not need a resistor:

https://forums.labja...?showtopic=1040

Hi....I have a question about this. In another thread (Post) you noted that:

-----------------
The LM34CAZ is a great temperature sensor. With no load resistor, you will get a range of about 60 to 300 degrees F. With a 4.7k resistor loading the LM34 output, you can get the full single supply range of 5 to 300 degrees F.
-----------------

I need to read a water temperature down to around 35 degrees F. Since I will need to add a resistor to the lm34caz to lower the readable temperature, is there any other benefit over the LM335?

Sorry for such a simple question, but I am just learning. If I use the LM34CAZ with the 4.7k resistor, do I install the resistor in the same way as the diagram earlier in this thread?

Thank you!!

[Frosty]

The LM335 works fine with the U12. It is used in our EI-1022 probe. The schematic you found looks like the "Basic Temperature Sensor" figure from the LM335 datasheet (national.com).

http://www.labjack.c...4751273;start=1

You might also consider the LM34CAZ, which does not need a resistor:

https://forums.labja...?showtopic=1040

Hi....I have a question about this. In another thread (Post) you noted that:

-----------------
The LM34CAZ is a great temperature sensor. With no load resistor, you will get a range of about 60 to 300 degrees F. With a 4.7k resistor loading the LM34 output, you can get the full single supply range of 5 to 300 degrees F.
-----------------

I need to read a water temperature down to around 35 degrees F. Since I will need to add a resistor to the lm34caz to lower the readable temperature, is there any other benefit over the LM335?

Sorry for such a simple question, but I am just learning. If I use the LM34CAZ with the 4.7k resistor, do I install the resistor in the same way as the diagram earlier in this thread?

Thank you!!

The LM34 is a quite different device, see the info in this thread https://forums.labja...h...893&hl=lm34 for the resistor/connection data.

[LabJack Support]

The resistor mentioned in topics 1040 and 1110 is for loading the output of the LM34, and accounts for the bias currents of the U12. That means you connected the resistor from output to ground. Since you are connecting the sensor to an analog input on the U12, you can just add a resistor from the AI terminal to a GND terminal. Note that the LM335 always needs a resistor, and it is for controlling the current not loading the output. The LM34 is available is more accurate grades than the LM335, and provides more output versus temperature change.

[ARDUINEM]

how about dht-11?

[LabJack Support]

We do support I2C, SPI, 1-wire, and SBUS, so consider something using those protocols.  For example, the SHT1x & SHT7x sensors  from Sensirion use SBUS.

 

The DHT11 & DHT22 look like they use an inconvenient custom serial protocol, but will have someone else look a little closer:

 

http://www.adafruit....heets/DHT22.pdf

[LabJack Support]

The DHT22 seems to use a protocol very similar to 1-wire, but the timing is different. The times are too small to use a script so firmware support would be required.

 

I don't recommend using this part.

 

 

If you only need temperature there are a lot of options. Here are a couple:

 

1-Wire: DS18B20

I2C: TMP75

 

Thermocouples are also easy to use with the T7.