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Arjen Hiemstra edited this page Jan 3, 2024 · 19 revisions

The CO2 Sensors

Itho RTF CO2 sensor

Integrates directly with the Itho unit and controls the unit:
https://www.ventilatieland.nl/artikel/25035/itho-daalderop-rft-co2-sensor-opbouw-met-bediening-230-volt-04-00045.html

For pairing this external sensor to the Itho unit see the manual https://ithodaalderop.compano.com/Data/Environments/000001/Attachment/Bijlage/A04_Ventilatie/A04_80_Accessoires/A04_80_04_RF%20sensoren/A04_80_04_01_RF%20sensoren/B01_05_MAN/01-01354-011%20%20Handleiding%20RFT%20CO2-sensor%20incl.%20bediening%20230V.pdf

When paired to the Itho unit, the sensor indicates ventilation speed (low, medium, high) and CO2 warnings with LED's.
When the CO2 level becomes over 1000 ppm, the fanspeed is increased, while the speed setting stays the same.
The CO2 level in ppm is available as item 'CO2level (ppm)' in the 'ithostatus' message.
This message can be retrieved via the web-api or MQTT.
To get the value from the JSON object (e.g. in Node-Red) use the format msg.payload["CO2level (ppm)"]. This is because of the embedded space.

Alternatively, the sensor can be paired to the add-on and that presents the CO2 level as item 'CO2' in the 'remotesinfo' message.
This message can be retrieved via the web-api or MQTT.
The Itho unit now does not respond to changes in CO2 level. Also the sensor's LED's do not give information from the Itho unit, since the add-on does not send information to the sensor.
The status sensor however still lights orange when the CO2 level is too high, > 2000 ppm.

Itho with built-in CO2 sensor (CVE-S optima inside)

For CVE units with built-in CO2 sensor (optima inside) a longer header is needed to be able to stack the CO2 sensor board on top of the add-on. If you would like to order the add-on with these longer headers, please mention it during check out (on Tindie) or select the the corresponding itho model during order ("CVE Optima met ingebouwde CO2 sensor" on nrgwatch.nl).

The I2C to PWM protocol is overruled by the CO2 sensor, meaning it is not possible to persistently set a fan speed using the PWM2I2C protocol, as it is overruled by the CO2 sensor. Virtual remote commands, such as 'low', 'medium' and 'high' do work as expected.

Some more info can be found on this tweakers.net forum post: https://gathering.tweakers.net/forum/list_message/69403538#69403538 (note: edit4 in this post is not relevant anymore for current hardware revisions)

Other CO2 sensors

For ongoing discussion on using CO2 sensors and their measurements, see Integration of Itho Daalderop CO2 + Relative Humidity sensor? issue on Github