GSS CozIR-Blink User manual

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CozIR®-Blink
Evaluation Board
User Guide

USER GUIDE
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Revision 1.2, 29 March 2021
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Copyright © 2021 Gas Sensing Solutions Ltd.
TABLE OF CONTENTS
INTRODUCTION ........................................................................................................................... 4
USB DRIVER ................................................................................................................................. 5
SOFTWARE INSTALLATION ........................................................................................................... 5
INSTALLING THE SENSOR.............................................................................................................. 5
EVALUATION BOARD CONCEPT .................................................................................................... 6
STANDALONE OPERATION............................................................................................................ 8
SENSOR POWER SUPPLY............................................................................................................... 9
Method 1 - External Power Supply .....................................................................................................9
Method 2 - USB Power Supply............................................................................................................9
Method 3 - Variable External Power Supply.....................................................................................10
SENSOR POWER CONSUMPTION MEASUREMENT....................................................................... 12
ENVIRONMENTAL CONDITION MONITORING.............................................................................. 12
EVALUATION BOARD BUTTONS, JUMPERS AND LED INDICATORS................................................ 12
SOFTWARE USER INTERFACE ...................................................................................................... 13
RUNNING THE SOFTWARE.......................................................................................................... 14
SENSOR SELECTION.................................................................................................................... 15
CO2SENSOR MEASUREMENT...................................................................................................... 16
OTHER ENVIRONMENTAL SENSORS ............................................................................................ 18
CURRENT MEASUREMENT.......................................................................................................... 19
GRAPHING SENSOR DATA .......................................................................................................... 20
ZERO-POINT SETTING THE SENSOR ............................................................................................. 21
ZERO IN NITROGEN...........................................................................................................................22
ZERO IN AMBIENT CONDITIONS .......................................................................................................22
ZERO IN A KNOWN GAS CONCENTRATION.......................................................................................22
PRESSURE COMPENSATION........................................................................................................ 23
BLINK MODE SETTINGS .............................................................................................................. 24
AUTO-ZERO FUNCTION .............................................................................................................. 25
AUTO-ZERO INTERVALS.............................................................................................................. 25
AUTO-ZERO LEVEL.............................................................................................................................25
SENSOR COMMUNICATIONS ...................................................................................................... 26
DATA DISPLAY ........................................................................................................................... 27
DATALOGGING........................................................................................................................... 29
TERMINAL VIEW ........................................................................................................................ 31
TERMINAL VIEW –UART READ ................................................................................................... 32

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TERMINAL VIEW –UART WRITE.................................................................................................. 33
TERMINAL VIEW –I2C WRITE...................................................................................................... 34
TERMINAL VIEW –I2C READ........................................................................................................ 35
MECHANICAL DIAGRAM............................................................................................................. 37
IMPORTANT NOTICE .................................................................................................................. 38
ADDRESS ................................................................................................................................... 38
REVISION HISTORY..................................................................................................................... 39

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INTRODUCTION
This evaluation board is designed to provide a fast and easy start for evaluation of the GSS CozIR®-
Blink-N sensor. The CozIR®-Blink-N sensor is designed to be power cycled and pre-programmed to
take one reading per power cycle. This means that power to the sensor must be removed and re-
applied before the sensor will take another reading. Power cycling can be done using the evaluation
board software, or manually.
The evaluation board brings several interfaces and interconnections shown in Figure 1.
The CozIR®-Blink-N Evaluation Board is designed to allow the user to evaluate all the hardware and
software functions of the sensor. This manual provides information about the board’s
interconnections, jumper settings, communications, and debug interfaces.
The sensor can be controlled by a PC application via the USB interface, or standalone and controlled
externally via connections to the sensor on the evaluation board.
The sensor and other supporting electronics can be evaluated using a PC software application. This
provides the user with a graphical user interface to all the main functions of the sensor, as well as a
terminal mode, allowing the user to write and read data directly from the sensor registers.
As well as evaluating the CO2sensor, the software application allows the user to monitor and store
other environmental conditions such as pressure, relative humidity, and temperature.
The evaluation board also has the capability to measure the current consumption of the sensor in
any of its operating modes, allowing the use to accurately assess real world power use over time.
Alternatively, the sensor can be completely separated from all the other electronics on the
evaluation board and controlled directly by the user via edge connectors. All data, control and
status pins of the sensor can be connected to connectors, J3, J4 and J5. Power is provided via a
separate edge power connector (J2), via USB (J1), or directly via header (J5).
For more technical information on the sensor, download the appropriate data sheet from here:
https://www.gassensing.co.uk/products/

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USB DRIVER
To interface to a PC, the evaluation board requires a USB-A to USB-Mini B cable and a USB driver to
function correctly. Recent versions of Windows will automatically identify and install the USB driver
when you plug in the lead.
If the USB driver is not installed, or the evaluation board will not connect to a COM port, please
download the USB driver from the FTDI website:
https://www.ftdichip.com/Drivers/VCP.htm
Choose “VCP Drivers” and select the correct driver for your operating system.
SOFTWARE INSTALLATION
The GSS evaluation board software is available direct from the GSS web site. Download the .zip file
to your computer. Unzip and click on Setup.exe and follow the instructions on the screen.
INSTALLING THE SENSOR
The sensor needs to be connected to the board. Rotate the fixing cams out of the way to allow
insertion of the sensor. When the sensor is correctly seated on the pin headers, rotate the cams into
place, clamping the sensor into place.
Insert the sensor before applying power to the board or connecting the USB interface. Refer to
figure 2 on the following page of this user manual to determine the correct sensor orientation.

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EVALUATION BOARD CONCEPT
Figure 1: Evaluation Board Key Components
The evaluation board consists of a USB interface device, which connects to an on-board
microcontroller. The on-board microcontroller connects to the sensor using either its UART
or I2C interface. The interface mode from the microcontroller to the sensor is user
selectable.
The microcontroller also interfaces to the environmental monitoring sensors. The
evaluation board comes with temperature, humidity, pressure, and current sensors.

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Figure 2: Top Side Evaluation Board
Figure 3: Bottom Side Evaluation Board

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STANDALONE OPERATION
The sensor can be completely isolated from the rest of the evaluation board electronics. This allows
the user to conveniently control the sensor directly via edge connectors J3, J4 and J5. To operate in
this manner, the DIP switches (S5) must be set to isolate the sensor from the microcontroller by
putting them into the off position.
Figure 4: DIP Switches (S5, shown in OFF position)
The evaluation board is shipped with the DIP switches set ON (see label on switch) to connect the
sensor to the on-board microcontroller by default. To isolate the sensor from the on-board
microcontroller, set the switches to OFF. Power supply connections to the sensor are described in
the following section.
The sensor switch connections on the DIP switches are listed below.
SWITCH POSITION
NAME
TYPE
DESCRIPTION
1
Rx_In
Digital Input
UART Receive Input
2
Tx_Out
Digital Output
UART Transmit Output
3
NC
Unused
Do not connect (For internal use only)
4
VDD1
Supply
Sensor supply voltage
5
NC
Unused
Do not connect
6
READY
Digital Output
Data ready pin. Pulsed high when data
ready
7
I2C_SDA
Digital Input/Output
I2C serial data input/output. Pull-up
resistor to VDD is provided on the
evaluation board.
8
I2C_SCL
Digital Input
I2C serial clock input. Pull-up resistor to
VDD is provided on the evaluation
board.
9
I2C_ENABLE
Digital Input
Set low for I2C interface mode. Leave
floating to select UART interface mode.
Pin status detected at power on.
10
NC
Unused
Do not connect

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SENSOR POWER SUPPLY
If the sensor is to be evaluated in isolation and separately from the evaluation board USB interface
and software, it must be provided with power. There are three methods to provide power to the
sensor. In all cases, the CozIR®-Blink-N must be powered cycled to function correctly. The CozIR®-
Blink-N is pre-programmed to take a single reading per power cycle. This means that power to the
sensor must be removed and re-applied before the sensor will take another reading.
Note the sensor must be powered via the USB interface (method 2) if the GSS evaluation software is
to be used.
Method 1 - External Power Supply
The sensor can be supplied from an external power source via the connector (J2). This connector
can accept either a 2.5mm or 2.1mm standard DC 5V power supply barrel plug. This drives a low
noise low drop out (LDO) regulator, which supplies the sensor via a FET switch.
The LDO regulator provides a stable 3.3V output to the sensor via switch S1. To enable this mode of
operation, switch S1 should be set to external power (EXT PWR). The LDO input voltage range is a
nominal 5V to 15V.
Power is only connected to the sensor when switch S2 is pressed. Sensor data must be read out from
the sensor when switch S2 is on. Releasing switch S2 will cut-off the power to the sensor.
In this mode, sensor data can only be retrieved from the sensor using the data interface on
connectors J3, J4 and J5. Please ensure the PL1 jumper is fitted.
Method 2 - USB Power Supply
Power is normally provided by a USB source. Plug J1 into a USB power source and set switch S1 to
USB power (USB PWR), see picture below. This drives a low noise low drop out (LDO) regulator,
suppling the sensor via a FET switch. The LDO regulator provides a stable 3.3V output to the sensor.

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Method 3 - Variable External Power Supply
The user can also drive the sensor directly with an external power supply, bypassing the on-board
low noise LDO and FET switch. This allows the user to evaluate the behaviour of the sensor with
different supply voltages or power sources. To enable this mode of operation, the following settings
need to be configured.
Connector/Jumper
Setting
Sensor Connection
J5, pin 1
Connect to external GND
GND
J5, pin 2
Connect to external VDD
VDD
J5, pin 4
Connect to external VDD
VDD1
PL1
Remove jumper. Isolates sensor from
rest of the evaluation board
-
PL2
Remove jumper. Isolates sensor from
rest of the evaluation board
-
The evaluation board has pull-up resistors for the I2C serial data input/output lines in each of these
modes. They pull-up to either the on-board 3.3V supply, or the external VDD on J5, pin 2 and pin 4.
All the sensor connections are enumerated on connectors, J3, J4 and J5, see figure 1. For a full
description of the sensor connections and functions, please refer to the latest version of the data
sheet at, https://www.gassensing.co.uk/products/.
Note that for the CozIR®-Blink-N to operate correctly in this mode, the external supply connections
on J5, pin 2 and pin 4 must be power-cycled. This means that all power to the sensor must be
removed, and then re-applied. The CozIR®-Blink-N will only take a new reading after it has been
power cycled. The time between a power down and re-application of power should be greater than 4
seconds to ensure the sensor is fully switched off. This will ensure the sensor is properly power
cycled. Failure to allow the sensor adequate time to power down may result in erratic performance.

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J3
PIN
NAME
TYPE
DESCRIPTION
1
I2C_SCL
Digital Input
I2C serial clock input. Open drain, external 3.3kΩ
resistor pulled high to VDD required
2
I2C_SDA
Digital
Input/Output
I2C serial data input/output. Open drain, external
3.3kΩ resistor pulled high to VDD required
3
Tx_Out
Digital Output
UART Transmit Output
4
Rx_In
Digital Input
UART Receive Input
J4
PIN
NAME
TYPE
DESCRIPTION
1
NC
Unused
Do not connect
2
READY
Digital Output
Data ready pin. Pulsed high when data ready
3
NC
Unused
Do not connect (For internal use only)
4
I2C_ENABLE
Digital Input
Set low for I2C interface mode. Leave floating to
select UART interface mode. Pin status detected at
power on.
J5
PIN
NAME
TYPE
DESCRIPTION
1
GND
Supply
Sensor ground
2
VDD
Supply
Sensor supply voltage
3
NC
Unused
Do not connect (For internal use only)
4
VDD1
Supply
Sensor supply voltage

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SENSOR POWER CONSUMPTION MEASUREMENT
The sensor evaluation board contains circuitry to allow the user to accurately measure sensor
current consumption. A high-precision, high-side current-sense amplifier is used to measure the
current through a 1.5ohm resistor R6. The signal is digitised by the on-board microcontroller.
The application software graphically displays the current draw of the sensor over the initial part of
the measurement cycle and displays the average current draw whilst it is powered up. The sensor
power consumption measurement application operates when using sensor power method 2. It
cannot be used when powering the sensor using method 1 or 3.
ENVIRONMENTAL CONDITION MONITORING
In addition to CO2measurement, the sensor evaluation board comes with the ability to measure
relative humidity, temperature, and pressure in real time. These functions operate independently of
the CO2sensor. The application software displays and can store these conditions. The evaluation
board must be powered either via the USB interface (method 2), or the external power supply
(method 1).
EVALUATION BOARD BUTTONS, JUMPERS AND LED INDICATORS
BUTTON
DESCRIPTION
S1
USB power or external power
S2
Blink mode. Applies power temporarily to the sensor (using method 1 or method 2).
Note switch is non-latching. Press to apply power, release to remove power.
S3
Unused
S4
Unused
S5
Evaluation board micro to sensor interface
S6
Reset MCU
JUMPER
DESCRIPTION
PL1
Enables power to the sensor using switch S2.
PL2
Allows sensor to be isolated from USB or S1 power connections. Remove jumper if
using external power via J5
LED
DESCRIPTION
LED1
Green. Shows Evaluation board is running
LED2
Green. Shows transmission of data to the board in UART mode
Red. Shows transmission of data to the board in I2C mode
LED3
Green. Shows transmission of data from the sensor in UART mode
Red. Shows transmission of data from the sensor in I2C mode

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SOFTWARE USER INTERFACE
All the main sensor and evaluation board functions are controlled through a single user interface,
displayed above. Hovering over a button will display the tips for that function.

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RUNNING THE SOFTWARE
The software may start automatically after installation. If it does not, you can start it from the
“Program” Menu in the Start Menu. Look for the filename GSS Customer Evaluation Board.The
opening screen is below.
To connect to the sensor, select the correct COM port from the drop-down Connection list, and
click the CONNECT button. The drop-down list will only show ports with active devices attached.
If you do not know the appropriate port select “device manager” on your PC, select Ports, and
unplug the SEB and then plug back in. The Com port will show up when the board is plugged in.

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SENSOR SELECTION
Select the correct sensor type and the full-scale range (CO2ppm) of the sensor.
The power LED1 will illuminate green showing the sensor evaluation board is running.

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CO2SENSOR MEASUREMENT
The CozIR®-Blink-N sensor is pre-programmed to automatically take a series of measurements, filter
the data, and output a single reading after power is applied. After completion of this process, the
CozIR®-Blink-N will automatically enter a low power state. The CozIR®-Blink-N will not take any
further measurements until after a power cycle.
The software interface allows the user to cycle the power at a set period, or to manually power cycle
the CozIR®-Blink-N. In both cases, the sensor is powered off as soon as it has completed the
measurement cycle. The power-on time is dependent on the ‘nPulse’ value. The time period is
between power on events.
To power cycle at a set period, select ‘Measure every seconds’, enter the required power cycle
period and press Set. Note the minimum period is also dependent on the ‘nPulse’ setting, see Blink
Mode Settings.

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The CozIR®-Blink-N takes a number of measurements and filters them to create a single reading.
Each measurement takes 200ms plus the sensor setup time. For an ‘nPulse’ setting of 16, the time
to report a reading is approximately 16*200ms + 300ms = 3.5s. If the time required by the sensor to
report a valid reading is lower than the minimum cycle time, the software will not accept the value
and the user will be reminded of the minimum value allowable for the ‘nPulse’ setting. After the
sensor has reported a valid reading, it is automatically powered down by the software.
To power cycle the sensor manually, set ‘Measurement Time’ to Manual Measurement. The sensor
will be power cycled, and a new reading will be taken when the user clicks ‘Manual Polling – CO2’.
Manually power cycling the sensor faster than the minimum time needed to create a valid reading
will result in erratic sensor performance.
After a manual power cycle, or after each power cycle period, the CO2reading will be updated in the
main sensor data display area.

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OTHER ENVIRONMENTAL SENSORS
The evaluation board also contains on-board temperature, humidity, pressure, and current sensors.
These can be set to take measurements automatically at a pre-set period or set to take readings
manually. Note the time period can be set independently of the CO2sensor read period.
For manual readings, click ‘Manual Measurement’. Manual readings can be taken for each sensor
including the CO2sensor by clicking on the relevant button. The user interface in the lower centre of
the screen will update each sensor value when ‘Manual Measurement’ is clicked.
Alternatively, the sensors can be programmed to take readings continuously at the rate set in the
dialogue box. Click on the ‘Measure every 5 seconds box’, set the measurement period and click on
‘Set’.
The user interface in the lower centre of the screen will update every time period.

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CURRENT MEASUREMENT
To measure current, the sensor must be in ‘Manual Measurement’ mode.
The current measurement function generates a real time graphical display of the current
consumption of the sensor.
To correctly measure average current, the period between power cycles must be specified. This is
done by entering a value in the ‘Measure every seconds’ box. In the example shown, the period is
300 seconds between power on events.
To measure average current, click on ‘Update’ Current (uA) in the Graph Data section.
The ‘Average Current’ displayed in the lower centre of the screen is the current consumed by the
sensor over a complete 300s power cycle period. Thus, the average current is defined as the current
consumed by the sensor during the measurement period when it is powered up (period defined by
the nPulse setting) divided by the total time between power on events.
Note that the sensor is powered down as soon as the CO2reading has been accessed by the host
controller.

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GRAPHING SENSOR DATA
The user can graph sensor data. Click on the appropriate sensor box to graph the data in the upper
central area of the user interface. Note, only one sensor can be graphed at a time.
The graph update rate is set to the measurement rate, defined by the ‘Measurement Time’ of the
CO2sensor, or by the Temperature, Humidity and Pressure Settings.
When the current graph is selected, the evaluation board will accurately measure and graph the
current consumed by the sensor over the measurement period. This can be updated by clicking the
update button or manually polling using the ‘Current’button. The key activity period is displayed
and the average current per power on cycle is shown in the output field in the lower half of the
display.
To perform current measurement, the automatic power cycling must not be selected. Unclick
‘Measure every seconds’ to disable this function. If the user tries to undertake current
measurement, the software will warn the user and not allow an update to be made. After a current
measurement, automatic power cycling can be re-enabled.