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GSS CozIR-Blink, User Manual

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GSS CozIR-Blink User Manual Download Page 21

USER GUIDE

 

Gas Sensing Solutions Ltd. 

Revision 1.2, 29 March 2021 

 

 

Page | 21     For regular updates, sign up at https://gassensing.co.uk 

Copyright © 2021 Gas Sensing Solutions Ltd. 

 

ZERO-POINT SETTING THE SENSOR 

 

There are a several methods available to the user to set the zero point of the sensor.  In all cases, the 
best zero is obtained when the gas concentration is stable, and the sensor is at a stable temperature.  
Note the zero-point settings are not cumulative and only the latest zero-point setting is effective. For 
example, there is no benefit in zeroing in nitrogen, and then zeroing in a calibration gas.  The sensor 
will store only the latest zero point. 

 

 

Summary of Contents for CozIR-Blink

Page 1: ...Gas Sensing Solutions Ltd Revision 1 2 29 March 2021 Page 1 For regular updates sign up at https gassensing co uk Copyright 2021 Gas Sensing Solutions Ltd CozIR Blink Evaluation Board User Guide ...

Page 2: ...ENSOR 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 CO2 SENSOR 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 ...

Page 3: ...021 Page 3 For regular updates sign up at https gassensing co uk Copyright 2021 Gas Sensing Solutions Ltd TERMINAL VIEW UART WRITE 33 TERMINAL VIEW I2 C WRITE 34 TERMINAL VIEW I2 C READ 35 MECHANICAL DIAGRAM 37 IMPORTANT NOTICE 38 ADDRESS 38 REVISION HISTORY 39 ...

Page 4: ...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 CO2 sen...

Page 5: ...ww 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...

Page 6: ...ts 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 humidit...

Page 7: ...sing Solutions Ltd Revision 1 2 29 March 2021 Page 7 For regular updates sign up at https gassensing co uk Copyright 2021 Gas Sensing Solutions Ltd Figure 2 Top Side Evaluation Board Figure 3 Bottom Side Evaluation Board ...

Page 8: ...solate 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...

Page 9: ...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 ...

Page 10: ...d The evaluation board has pull up resistors for the I2 C 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 ...

Page 11: ...tor 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 I2 C interface mode Leave floating to select UART interface mode Pin sta...

Page 12: ... the ability to measure relative humidity temperature and pressure in real time These functions operate independently of the CO2 sensor 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...

Page 13: ... updates sign up at https gassensing co uk Copyright 2021 Gas Sensing Solutions Ltd 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 ...

Page 14: ...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 th...

Page 15: ...For regular updates sign up at https gassensing co uk Copyright 2021 Gas Sensing Solutions Ltd SENSOR SELECTION Select the correct sensor type and the full scale range CO2 ppm of the sensor The power LED1 will illuminate green showing the sensor evaluation board is running ...

Page 16: ...ally 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 p...

Page 17: ...he 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 clic...

Page 18: ... period can be set independently of the CO2 sensor read period For manual readings click Manual Measurement Manual readings can be taken for each sensor including the CO2 sensor 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 continuo...

Page 19: ...e 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 c...

Page 20: ...tings 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 p...

Page 21: ...hods available to the user to set the zero point of the sensor In all cases the best zero is obtained when the gas concentration is stable and the sensor is at a stable temperature Note the zero point settings are not cumulative and only the latest zero point setting is effective For example there is no benefit in zeroing in nitrogen and then zeroing in a calibration gas The sensor will store only...

Page 22: ...sor will be zeroed assuming the ambient environment is 400ppm The CO2 concentration fresh air zero level is programmable over a range from 0ppm to the full scale of the sensor The software default is 400ppm as the fresh air CO2 concentration value However the user can write a different fresh air value to the sensor if desired To write a different fresh air CO2 concentration value to the sensor set...

Page 23: ...rent from the calibration setting It is possible to configure the sensor to correct for this effect by writing the actual or reference mean barometric pressure in mbar to the sensor This can be done as part of the initial set up process or updated at any time during use Write the decimal value in mbar into the dialogue box and click Pressure Comp In all cases the sensor polling mode needs to be sw...

Page 24: ...easurements used to create a single filtered value is determined by setting the nPulse value Set nPulse by entering the value into the No Pulses data entry box The default value is 16 Reducing the nPulse value decreases the time taken to acquire the reading but at the expense of measurement noise Each value of nPulse is equivalent to one 200msec measurement Therefore the value of nPulse also sets ...

Page 25: ...mand AUTO ZERO INTERVALS The auto zero period can be programmed by the user For the CozIR Blink N an auto zero is set based on the number of sensor power cycles Add the number of power cycles in the No Cycles data entry box and click Auto Zero AUTO ZERO LEVEL The background concentration will depend on sensor location Ambient levels are typically in the range of 400ppm 450ppm The factory default i...

Page 26: ...e sensor has two control interface modes To ensure the sensor behaviour is representative of real world use the evaluation board microprocessor will communicate with the sensor in either UART or I2 C mode dependent on this setting To set the interface mode click on the appropriate dialogue box Power cycling is automatically disabled during changes It can be manually enabled after the change ...

Page 27: ...interface Sensor Data Type Description Units Sensor ID No Unique sensor ID N A CO2 CO2 concentration ppm Temperature Ambient temperature C Pressure Ambient pressure mbar Average Current Current drawn by the sensor over a power cycle period see description for more details uA Relative Humidity Ambient relative humidity RH Absolute Humidity Ambient absolute humidity grams per cubic metre This data i...

Page 28: ...g Solutions Ltd Sensor Data Type Description Units Mode Measurement mode Poll Period Measurement update period Seconds Filter Digital filter setting Decimal Last Zero Value Value used to re zero the sensor ppm Pressure Comp Pressure value used by CO2 sensor mbar Hours Ran No value This data is static and represents the configuration of the CO2 sensor ...

Page 29: ...gular updates sign up at https gassensing co uk Copyright 2021 Gas Sensing Solutions Ltd DATALOGGING CO2 and other sensor data can be recorded To initiate the recording process click Record To stop the recording process click Stop Clicking on Record brings up the following screen ...

Page 30: ...6 28 108 1196 13 01 21 11 36 40 478 1205 23 96 1014 38 35 38 7 68 13 01 21 11 36 40 483 23 96 1014 38 35 38 7 68 13 01 21 11 36 49 486 1187 13 01 21 11 36 53 664 23 98 1014 37 35 39 7 69 13 01 21 11 36 58 480 1184 13 01 21 11 37 07 473 1221 13 01 21 11 37 08 673 24 1014 38 35 48 7 72 13 01 21 11 37 16 466 1222 13 01 21 11 37 25 475 1216 13 01 21 11 37 25 491 24 02 1014 38 35 37 7 7 13 01 21 11 37 ...

Page 31: ...ettings are available to the user using the Terminal View The Terminal View allows the user to read and write directly to the CO2 sensor For a Blink N sensor to accept commands the sensor MUST NOT be in polling mode Before sending any commands to the sensor it must be power cycled using the reset button in the Terminal View window The Terminal View window will show S0 followed by S1 to say that it...

Page 32: ...tton A Z command must be sent first in UART mode Sending the Z command clears the C02 value giving the response Once the sensor has responded with standard commands may be sent to the sensor via the terminal window To read a value write the command into the dialogue box and click Send Examples of commands are shown above a is the returned value for the npulse setting In this case the value is 16 s...

Page 33: ...e command into the dialogue box and click Send In this example the X Command is shown X is the command to zero the sensor in a known gas concentration in this case 1000ppm Sending a command followed by an integer X 1000 in this case will write the value into the appropriate register The sensor will automatically respond with an internal reference variable decimal value corresponding to that settin...

Page 34: ...on The S0 and S1 indicate that a power cycle has occurred after selecting the Reset button To write to an I2 C register the instruction must be formatted correctly Writes are formatted as wr followed by the number of bits to write followed by the register number in decimal followed by the decimal value to write to the register For example wr8 5 1 will write the value 1 as an 8 bit word to register...

Page 35: ...ht 2021 Gas Sensing Solutions Ltd TERMINAL VIEW I2 C READ To read from an I2 C register the instruction is formatted as rd followed by the number of bits to read as noted in the datasheet followed by the register number in decimal For example rd16 2 will read 16 bits from register 2 which in this case will return the CO2 value in ppm ...

Page 36: ... 2021 Gas Sensing Solutions Ltd The in the I2 C commands denotes to the evaluation board that a special command must be pre processed before passing on to the sensor If the interface is set to I2 C mode and if the is missing the evaluation board assumes the command is a UART command and sending it on to the sensor will return a timeout ...

Page 37: ...USER GUIDE Gas Sensing Solutions Ltd Revision 1 2 29 March 2021 Page 37 For regular updates sign up at https gassensing co uk Copyright 2021 Gas Sensing Solutions Ltd MECHANICAL DIAGRAM ...

Page 38: ... products are not intended for use in life support systems appliances nuclear systems or systems where malfunction can reasonably be expected to result in personal injury death or severe property or environmental damage Any use of products by the customer for such purposes is at the customer s own risk GSS does not grant any licence express or implied under any patent right copyright mask work rig...

Page 39: ...egular updates sign up at https gassensing co uk Copyright 2021 Gas Sensing Solutions Ltd REVISION HISTORY DATE RELEASE DESCRIPTION OF CHANGES PAGES 16 12 2020 1 0 First revision All 12 01 2021 1 1 Major update to all sections All 29 03 2021 1 2 Updated current consumption P 19 ...

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