Instructions

2
Calibrating the Sensor
CO
2
Gas
The CO
2
Gas sensor is factory calibrated. For many experiments, it will not be
necessary to calibrate this sensor when using this channel. However, for best
accuracy, the sensor can be calibrated using a one-point calibration based on a
sample of outside air. Atmospheric air typically has a carbon dioxide
concentration of around 400 ppm. Actual levels in your area may be slightly
higher due to localized influences such as automobile or industrial emissions of
carbon dioxide. To calibrate Go Direct CO
2
Gas
1. Fill the 250 mL Nalgene bottle to the brim with water, take it outside, and
dump the water to ensure it is then filled with fresh air. While still outdoors,
insert the sensor into the gas sampling bottle that now contains fresh outside
air. Take the bottle and sensor to where the calibration will be done.
2. Start the software and identify your sensor, if necessary. Let the sensor warm
up for at least 180 seconds before continuing.
3. When the sensor has warmed up (readings should have stabilized), calibrate
the sensor using a one-point calibration. Enter a value of 400 ppm for the
sample of air collected. Once finished, the sensor should read very close to
400 ppm.
Temperature
The temperature sensor is factory calibrated and cannot be calibrated by the
user.
Humidity
The relative humidity sensor is factory calibrated and cannot be calibrated by
the user.
Specifications
CO
2
Sensor
Type NDIR
Range 0–100,000 ppm
Accuracy 0 to 1,000 ppm ±100 ppm
1,000 to 10,000 ppm ±5% of reading +100 ppm
10,000 to 50,000 ppm ±10% of reading
50,000 to 100,000 ppm ±15% of reading
Resolution 1 ppm CO
2
Warm-up time 180 seconds
Gas sampling mode diffusion
Temperature Sensor
Type IC
Connected and charging Blue and Green LED solid when sensor is con-
nected to Graphical Analysis via USB and unit
is charging. (Green LED is obscured by the blue
one.)
Connected, fully charged Green LED solid when sensor is connected to
Graphical Analysis via USB and the unit is fully
charged.
Charging via USB,
connected via Bluetooth
Blue LED is solid and green LED is flashing, but
the green flashing LED looks white because it is
overwhelmed by the blue.
Identifying the Sensor
When two or more sensors are connected, the sensors can be identified by
tapping or clicking Identify in Sensor Information.
Using the Product
Connect the sensor following the steps in the Getting Started section of this user
manual.
Channels
Go Direct CO
2
Gas has three measurement channels:
l CO
2
Gas
l Temperature
l Relative Humidity
CO
2
Gas
This channel measures the carbon dioxide concentration in the air. Units can be
changed from parts per million (ppm) to parts per thousand (ppt), percent (%), or
mg/m
3
. See www.vernier.com/til/3845 for more information. The readings are
temperature compensated regardless of whether the temperature channel is
activated. This is the default channel that is active when the sensor is
connected.
Temperature
This channel measures air temperature inside the sensor. Units can be changed
from °C to °F or K. This channel is not active by default when the sensor is
connected.
Relative Humidity
This channel measures the relative humidity of the air. It is not used to
compensate CO
2
gas readings. This channel is not active by default when the
sensor is connected.