Why is VOC shown in µg/m³ when the datasheet uses ppb?

The sensor reports ppb. Its Zigbee definition converts the value to µg/m³ by multiplying by 4.5, which is the factor Sensirion uses for its reference TVOC mixture. The air quality level is worked out from the ppb value.

How often does it report?

By default every 10 minutes when values are stable. A change of 0.1 °C, 3 % RH or 10 ppb VOC is reported sooner, but not more often than once a minute. A hub that supports reporting configuration can change these settings.

How long do the batteries last?

frient rates two AA alkaline cells for 2 years when reporting every 5 minutes. Replace them at 2.5 V; the red LED also blinks twice every 60 seconds when the battery is low.

What do the VOC levels mean?

Develco maps the reading to five levels: excellent below 65 ppb, good from 65 to 220 ppb, moderate from 220 to 660 ppb, poor from 660 to 2200 ppb and unhealthy from 2200 ppb. Poor calls for more ventilation and unhealthy for intense ventilation.

Develco AQSZB-110 Zigbee air quality sensor

Compatibility

Compatible with EpiSensor Edge over Zigbee.

Pair it with the Zigbee radio on an EpiSensor Gateway. Edge reads it locally on the Gateway.

Edge reads 7 values from it, listed under Interface.

Connect it with

Gateway ZGW-20
From €899 ex VAT Configure Gateway

Specifications

The VOC sensor measures in parts per billion from 0 to 60,000 ppb, with a resolution of 1 ppb up to 2008 ppb, 6 ppb up to 11,110 ppb and 32 ppb above that. Develco publishes a five-level interpretation of the reading, from excellent below 65 ppb to unhealthy from 2200 ppb, taken from Sensirion’s TVOC guidance. Temperature has 0.1 °C resolution with a typical accuracy of ±0.2 °C; humidity has 1 % RH resolution with a typical accuracy of 2 % between 20 and 80 % RH.^2, 3

Power: Battery. Two exchangeable AA alkaline cells, rated for 2 years when reporting every 5 minutes. Develco says to replace them when the battery voltage reaches 2.5 V.²
VOC range: 0 to 60,000 ppb²
VOC resolution: 1 to 32 ppb, coarser at higher readings³
Temperature range: 0 to 50 °C²
Temperature accuracy: ±0.2 °C typical, 0.1 °C resolution²
Temperature sample time: 30 s²
Humidity range: 0 to 100 % RH²
Humidity accuracy: 2 % typical between 20 and 80 % RH, 1 % RH resolution²
Operating humidity: 10 to 95 % RH, non-condensing³
Ingress protection: IP20¹
Dimensions: 70 × 70 × 21 mm²
Weight: 29.1 g²
Wireless: Zigbee, Home Automation profile, end device²
Radio: -92 dBm sensitivity, +4 dBm typical output power²
Firmware updates: Over the air (Zigbee OTA cluster)³

Where it is used

VOC, temperature and humidity in offices, meeting rooms and classrooms, where a battery unit avoids new cabling.
Indoor environmental monitoring
Showing when rooms need more ventilation, next to the energy used by the air handling plant.
HVAC energy monitoring for commercial buildings
Humidity in stores and archives where valuable items are kept, within its 0 to 50 °C range.

Interface

On the Zigbee network it joins as a sleepy end device.³

Readings and settings, with units and ranges where Develco publishes them.

Download

Reading	Unit	Range or values	Access
Measurements 4
VOC	µg/m³	-	Read only
Air quality	-	`excellentgoodmoderatepoorunhealthyout_of_rangeunknown`	Read only
Temperature	°C	-	Read only
Humidity	%	-	Read only
Diagnostics 3
Battery	%	0 to 100 %	Read only
Voltage	mV	-	Read only
Battery low	-	Binary state	Read only

VOC comes from a manufacturer-specific cluster (0xFC03, manufacturer code 0x1015) on endpoint 38, not a standard Zigbee measurement cluster. Temperature and humidity use the standard clusters on the same endpoint.³

The sensor measures VOC in ppb. Its Zigbee definition converts that to µg/m³ by multiplying by 4.5, the factor Sensirion gives for its reference TVOC mixture, and derives the air quality level from the ppb value using Develco’s five-level table.^3, 6

Battery voltage is reported in steps of 100 mV. The Zigbee definition maps 2.5 V to 0 % and 3.0 V to 100 %.^3, 5

The sensor checks in with its parent every 15 minutes. After five missed replies, up to 1 hour 15 minutes, it starts searching for the network again.³

Setup

Open pairing in Edge
In Edge, open pairing on the Gateway’s Zigbee network before you power the sensor.
Insert the batteries
Fit two AA cells. A sensor that has never joined a network starts searching straight away, and its LED flashes once a second until it joins.³
Or reset a used sensor
If the sensor was on another network, press and hold the button. The LED steps through the button menu, one mode every 5 seconds; release it when it indicates factory reset. The sensor clears its network settings and searches again.³
Confirm the join
The LED stops flashing when the sensor has joined. Check that Edge identifies it as Develco AQSZB-110.³
Mount it and check a reading
Mount it indoors in a heated room. Compare the first temperature and humidity reports with a reference instrument placed beside it; with default settings a new report arrives at least every 10 minutes.³

Common questions

Why is VOC shown in µg/m³ when the datasheet uses ppb?: The sensor reports ppb. Its Zigbee definition converts the value to µg/m³ by multiplying by 4.5, which is the factor Sensirion uses for its reference TVOC mixture. The air quality level is worked out from the ppb value.^3, 6
How often does it report?: By default every 10 minutes when values are stable. A change of 0.1 °C, 3 % RH or 10 ppb VOC is reported sooner, but not more often than once a minute. A hub that supports reporting configuration can change these settings.^2, 3
How long do the batteries last?: frient rates two AA alkaline cells for 2 years when reporting every 5 minutes. Replace them at 2.5 V; the red LED also blinks twice every 60 seconds when the battery is low.^2, 3
What do the VOC levels mean?: Develco maps the reading to five levels: excellent below 65 ppb, good from 65 to 220 ppb, moderate from 220 to 660 ppb, poor from 660 to 2200 ppb and unhealthy from 2200 ppb. Poor calls for more ventilation and unhealthy for intense ventilation.³