Hello!

 

I am a student currently working on a project where I would like to read out humidity and temperature data from the Thunderboard Sense 2. This board has an on-board SI7021 chip. I tried to use the humitemp example as a template but that example is for a SI7013. I found the SI7021.c and SI7021.h files in the demo's of the Thunderboard Sense 1. I am assuming that those are identical for the Thunderboard Sense 2.

When trying to read out data, I keep getting error codes 1 and 2 ("SI7021_ERROR_I2C_TRANSFER_NACK" & "SI7021_ERROR_I2C_TRANSFER_FAILED").

 

Is it possible to describe in some basic steps what the code should do? I don't really know when (and if) I have to initialize the internal I2C bus.

 

I am also unsure about where to post this question. I think this is the best place, since my problem is with the SI7021 chip.

 

Thanks in advance!

 

Best regards

Lander

This forum is for support for the following products only:

 

Optical sensors -

 

Si1102

Si1120

Si1132

Si1141

Si1142

Si1143

Si1145

Si1146

Si1147

 

RH/Temp sensors -

Si7005

Si7006

Si7007

Si7013

Si7015

Si7020

Si7021

Si7022

Si7023

Si7050

Si7053

Si7054

Si7055

Problem is exactly as stated.

Following the directions using the Si115x EVB part does not work.  I get various error messages. When I go to the Si115x Control Panel and hit "Sommit Settings View Waveform" I get the error message "Unable to communicate with EVB"   When I choose any demo from the drop-down list in the Si115x Main Panel is hit LAUNCH DEMO, a window pops up saying "Configuring Part..."  but then an error window follows:  "Demo Execution Error!  Please select the UV/ALS DIP Switch and power cycle the board"   

I do all this a dozen times, for each demo, same error message every time. 

I have the correct DIP switch settings.  It doesn't matter which one I use;  they are do not function at all. 

Please help.  This is already very frustrating.  Your website is impossible to search correctly.  Search results having nothing at all to do with this EVB or Si115x.   Software seems scattered all over the place without any up-to-date central repository.     

Hello,

I am using the SI7006 in a device and need to use as little energy as possible. According to the datasheet the sensor draws up to 3.8uA when not measuring (standby mode). I also read that the sensor automatically enters standby mode whenever no measurement and no I2C communication is active. However, my sensor continuously draws 330uA (this increases slightly during measurements). Power supply is 3V, same for the I2C logic levels. I've tested over multiple sensors and they all show the same behaviour. Am I missing something?

Thanks,

Jan

PS: If I swap the SI7006 for a SHT21 (which seems have an identical footprint and command set) everything works as it is supposed to.

I do have 3 Si7060 on 2 different boards and all show about 4deg higher temperature than ambient. The room temperature is about 24deg C and the thermometers all show about 28deg C.

The sensor is placed about 1.5cm away from any other component on the PCB. I do read the temperature in one burst mode once a second (Write 0x04 to 0xC4, than read 2 bytes from  0xC1 with autoinc enabled).

The raw values is about 0xAFxx (e.g. 0xAF57) and that is without the new data flag 0x2F57 translating to ~28.3deg C. Is the calculation correct?

使用si7051设计了一个温度检测产品，测试过程中发现，在上电启动时，偶而会发生si7051无响应的现象。通过示波器跟踪发现，I2C主机发送从机si7051的地址时，si7051是有ACK应答的。但是之后I2C主机再发送测试命令0xF3或0xE3的时候，si7051就一直无ACK应答响应。进入无响应状态后，即便再发送复位指令也没有任何反应，这时连I2C主机发送从机si7051的地址都没有ACK应答了，只有断电，等待大概几分钟才可能正常启动。这样的现象不是每次上电都发生，有时是工作正常的，有时是异常的。I2C所有的操作，比如地址，命令，时序等都是正确的，否则也不会有正常工作的时候。请问这样的现象是什么问题造成的？

Hi,

 

I can't get this software tool to work with both, my IRMFB-EB and IRSLIDER2EK evaluation kit. The problem is that when I click on "view waveform" I don't see anything to happen. We have tried it on several computers.

 

The documentation is telling me that I need the "Si114x performance analysis tool", but where can I find it?

 

What can be wrong here....?

 

Thanks.

As I've read on this site, the Si1132 is NRND; the Si1133 is recommended to be used instead. But what about spectral response of the Si1133. Is it the same as of the Si1132 ?

To whom it may concern, the datasheet does not include any information concerning the RoHS Compliancy for the Si7021-A20-GM1R so it can't be used as proof of RoHS Compliancy. We are using this part in one of our products and need a RoHS Certificate or some form of documentation stating RoHS Compliancy for our document control. I need this as soon as possible. It is holding up the release of a product. Thank you, Roger

I am using SI7051, that is Si70 family. I want to know this temp. IC (SI7051) can compensate the humidity effect by the environment?

From the doc. of  "AN607: Si70xx Humidity and Temperature Sensor Designer’s Guide" - "The Si70xx family uses state-of-the-art sensing technologies to create precise monolithic humidity and temperature. Can it also apply on SI7051?

sensors".

Hi, we use the Si7051 on a few products and have been for the last 2-3 years.  A recent build of 30 units resulted in 6 of them with Si7051's not working.  Reflowing the parts does not fix the problem and debugging them showed there is no response from the sensors over I2C.  The Si7051 sensors were replaced and the replacements worked correctly.

We are trying to identify if the sensors broke at our CM or if they are factory defects.  And in either case, how we can avoid future failures.  Are there any known problems with these parts?  Do sensors get individually tested at Silicon Labs?  Can you provide any advice for future builds?

Thanks for any help, and let me know if I can provide more information.

Steve

I'm using the SI7021-A20 sensor for relative humidity readings in a closed and dry container.
The container has desiccant in it, so the humidity readings are very low: around 1%, but also 0%.

When the temperature is cycled from +20°C to +80°C to -40°C to +20°C we see clipping in the RH value when the temperature goes below 0°C.

This happens for all Si7021 chips we use. Please see attached a plot for temperature and relative humidity reading.
Note: the temperature reading is not from the Si7021 chip, we use a different chip for that. I can provide you with the Si7021 temperature data next Thursday.

As can be found in the datasheet on page 21 section 5.1.1. Measuring Relative Humidity:

We incorporate this formula in reading the RH from the sensor.
We added the following logic;
1) When the RH_Code is below 3146 we set %RH to 0 and
2) When the RH_Code is above 55574 we set %RH to 100

Below a plot with the temperature and the relative humidity versus time.

I also read the post on:
https://www.silabs.com/community/sensors/forum.topic.html/si7020_humidity_da-N786
Which redirects to support system case 00098157, but I cannot find that on your website...

Hi, 

i am doing IOT Based Smart parking Application. Please Suggest me which proximity sensor will be good for Car parking application. it should be work with  low power ,indoor and outdoor parking lot. 

hi

1) I want to read the data from Si7005 (USB-DONGLE) directly in to the LabVIEW rather by using the manufacturer provided software.

I am currently using Si7005 (USB-DONGLE) (https://www.silabs.com/documents/public/user-guides/Si7005USB-DONGLE.pdf ) to record Humidity/temperature using the an NI based software provided by the manufacturer.

I am using LabVIEW 2014 SP 1 32 bit. Kindly help me out to read the data directly in to the LabVIEW, please.

2) Please let me know the formula used by the software to convert the reading in to RH and temperature ?

3) How can the relative humidity or water-content in other gas (such as helium) can be measured using this sensor? Is their any way, please ?

Yours sincerely,

Syed