I'd like to connect a Vaisala GMP222 CO2 probe to a CR1000 data logger. I'm a novice with CS loggers but keen to learn!
I dont have the user guide for the probe but think the wiring for the sensor is:
Pin Colour Analog signal RS-232C
1 White TX
2 Brown TX
3 Green RX
4 Yellow Signal + -
5 Grey Supply Gnd Supply Gnd
6 Pink +11-36V DC +11-36V DC
7 Blue RX
8 Shield Signal Gnd -
I understand I can use a single ended voltage measurement (pin 4 to H, pin 5 to Gnd, pin 8 Gnd). With this wiring I get a voltage measure from this but dont know how to convert it to CO2 ppm.
Can anyone reccommend a better approach?
You need one thing called Vaisala’s GMM220 transmitter modules at first.
Then you can think about how to convert voltage to PPM of CO2 by measuring current or voltage output? Or you can connect the module to CR1000 through RS232 and directly get a digitial output.
I have run CR1000's with Licor CO2 analysers which have a 0-5v output. The CO2 concentration can be calculated from the output voltage
where V is the measured voltage, XF is the full scale value for CO2 output XZ is the zero value, Vmax is the full scale DAC output voltage
Maybe you can help me! I am repurposing a CR1000 to measure CO2 with a Vaisala GM70. However I cant fund the pin-out onfo anywhere to locate the signal pin - where did you get your info from?
Yes, the analog should be offset of 0. The multiplier is the full scale CO2 range divided by the full scale voltage in millivolts.
For example, a unit with a 2000ppm max CO2 range and a 0-1Volt output would have a multiplier for VoltSe of 2000ppm/1000millivolts = 2.0
Wondering if anyone has thoughts here for a similar setup....
Vaisala 343GMP Co2 probe
Allows 0-5V analog output range, 5V (voltage high)= 0.00-100,000.00 ppm (adjustable), beyond 10-20,000ppm, analog signal becomes very distorted.
Using a very basic singled ended command with ->
multiplier = high voltage ppm (100,000) / voltage range (5000mV) = 20 ppm/mV = multiplier (20)
Trying to setup serial coms, works great with the PC/terminal, but unable to get the logger to communicate through ComPort.
Very inexperienced with serial programming, but fairly confident with analogue measurements - attaching the script
'CR1000 Series Datalogger 'Date: June 24/2021 'Program author: Mark 'Declare Constants 'Declare Public Variables 'Example: Public PTemp, Batt_volt Public co2string As String * 30, SplitStrings(3) As String * 16 Public FloatValue As Long Public IntegerValue As Long Public NBytesReturned 'Declare Private Variables 'Example: 'Dim Counter 'Define Data Tables. DataTable (Test,1,1000) 'Set table size to # of records, or -1 to autoallocate. DataInterval (0,15,Sec,10) Minimum (1,Batt_volt,FP2,False,False) Sample (1,PTemp,FP2) Sample (1, IntegerValue, FP2) EndTable 'Define Subroutines 'Sub 'EnterSub instructions here 'EndSub 'Main Program BeginProg SerialOpen(Com1, 19200, 0, 0, 500) Scan (1,Sec,0,0) PanelTemp (PTemp,60) Battery (Batt_volt) SerialInRecord(Com1,co2string,&h02,0,&h0D03,NBytesReturned,01) SplitStr (SplitStrings(),co2string,",",3,5) FloatValue=SplitStrings(1) IntegerValue=SplitStrings(2) 'Enter other measurement instructions 'Call Output Tables 'Example: CallTable Test NextScan EndProg