Aeroponic System Project

[bestla.sas]

Hello,

We have an aeroponic system project, we want to measure the following variables in four chambers:

• Temperature
• Relative humidity
• CO2

So, we will need four measuring points (preferably on the BACnet/IP protocol) to be interfaced to a computer (which will do the data logging).

We have explored CO2-W-TH products and we believe they can be useful to us.

However, if you have other similar technologies we can study its integration, or just confirm that this product meets our expectations.

Thank you very much,

[maurice]

Yes, several clients have been using this sensor for hdroponics. The sensor can operate up to 10,000 ppm which makes this popular with the marijuana growers.

CO2 Sensor - Bravo Controls

[bestla.sas]

Hi Maurice,

We are a little disappointed because we believed in the reliability of the CO2-W-TH product readings. The disparity between temperature and humidity readings does not bother us at all. But the CO2 readings are very different.

We want to know if it is necessary to carry out a calibration procedure with these devices and how we can do it.

Thank you for responding asap.

PS: The sensors are already installed in the chambers of our aeroponic system.

[bestla.sas]

Here some pictures:

[maurice]

There is a self calibration mode which requires that the room go down to 400 ppm a couple times per week. This is the background C02 level on Earth right now. If the room never gets down to that level you should disable the automatic background calibration feature, the default is off so it may well be off already. To calibrate the sensor you could take it outside one time and adjust the offset to make it match 400 ppm. Similarly for the temperature and humidity you can calibrate those the same way to match your reference instrument. Normally this is done in a chamber at several readings. Use the T3000 software to get at these calibration features, it can be downloaded from the product pages.

[bestla.sas]

Is it necessary to do it through the T3000 software or with a software like Yabe or directly on screen is it possible to see/change this calibration features?

We do not want to unmount the devices, we could perform a calibration with a reference instrument

[maurice]

The user interface is pretty handy, you can calibrate the sensors there and get at all the settings. Once you are done the initial setup you don’t need T3000 anymore, you can use your own software to access the Bacnet and Modbus objects.

Here’s a preview of what you will see from the T3000 UI, you will need to connect over RS485 or Wifi if it has that option. You can adjust the protocol and baud rate from the keypad menu system, hold the leftmost and right most buttons down at the same time for about five seconds to get into the menu system.

[bestla.sas]

I’m using T3000 software.

The 4th button (from left to the right) isn’t able. I put two devices outdoor and let it there by 30 mins) after that I use “calibration” field (in INPUT tab) to adjust to 410 ppm. Later I put both devices indoor and they come crazy with CO2 readings. Now (after 1h) one of them come back to 410 ppm reading and the other one stay in 900 ppm.

So is pretty difficult to calibrate these devices and we aren’t sure the reliability of CO2 readings.

[bestla.sas]

Could you give us a tutorial to perform correctly the CO2 calibration of CO2-W-TH devices?

I’ll tell you how I did the calibration procedure using the T3000 software:

I left the devices outdoors for an hour and then set the offset to get a reading of 410 ppm. In one device the offset was negative (-18) and in the other positive (10).

Then I put them in a room and observed the next day that while one stabilized at 1100 ppm the other one did at 970 ppm.

I then disconnected both devices from the power supply and reconnected them. The one with a negative ofsset has a frozen reading at 99 ppm and the other one also froze at 410 ppm.

Every time a device is restarted it assumes that the current CO2 concentration is 410 ppm?

Why are the readings frozen?

[bestla.sas]

Well, there is still no answer from you and we are still experiencing problems with this product (CO2-W-TH).

We have found that every time we restart the device it calibrates itself with the current CO2 concentration at 400 ppm (which is not really).

We have then adjusted the offset. However, we see that the sensor is stuck at that figure, even though the CO2 concentration has changed.

On the other hand, it is very slow to register variations. It takes almost 1 minute to register the CO2 variation.

All is not lost. We have also performed tests with AL-CO2-W. It responds much faster and the readings are close to our reference device.

Do we want to know the possibility of changing the CO2-W-TH for AL-CO2-W? Of course, we would pay the difference.

We believe that the CO2-W-TH product is not a fully functional product for our project and we also require WiFi support.

Please let us know how the replacement process works. Thanks !

[maurice]

My apologies for not checking in here sooner. Our engineer will read through this and reply shortly.

[bestla.sas]

Hi Maurice ! Nobody contact me until now. Please tell me if we could replace the devices?

[PHT]

@bestla.sas

We have found that every time we restart the device it calibrates itself with the current CO2 concentration at 400 ppm (which is not really).

I think I saw maurice mention upthread that there is a way to disable the auto-calibration feature? I assume this is done through the t3000 interface but I don’t see anywhere to toggle that option in the screenshots in this thread. Maybe someone with more experience can chime in here?

[maurice]

This is the view of the feature from the Airlab sensor, it is similar to how it will appear in the basic C02 sensor, just click on the dialog and enter your parameters.

[maurice]

We stand behind the product but if you are having troubles and giving up then we will work with you to send them back. Please send an email for more discussions.