CS7500 (Measure LI-7500)

The CS7500 instruction is used to measure an LI-7500(A) LI-COR Open Path CO2 and H2O gas analyzer.

Syntax

CS7500 ( Dest, Reps, SDMAddress, CS7500Cmd )

The following example measures a CSAT3 and a CS7500 (LI-7500).

Public wind(5)
Public irga(5)
Alias wind(1) = Ux
Alias wind(2) = Uy
Alias wind(3) = Uz
Alias wind(4) = Ts
Alias wind(5) = sonic_diag
Alias irga(1) = CO2
Alias irga(2) = H2O
Alias irga(5) = press
Alias irga(4) = irga_diag
Units wind = m/s
Units Ts = C
Units sonic_diag = arb
Units CO2 = umol/mol
Units H2O = mmol/mol
Units press = kPa
Units irga_diag = arb

DataTable (ts_data,TRUE,-1)
    DataInterval (0,0,mSec,10)
    CardOut (0,-1)

    Sample (5,Ux,IEEE4)
    Sample (4,CO2,IEEE4)
EndTable

BeginProg
    SDMSpeed (30)
    Scan (50,mSec,3,0)
      CSAT3 (Ux,1,3,91,20)   
      CS7500 (CO2,1,7,6)
      CO2 = CO2*44
      H2O = H2O*0.018

      CallTable ts_data
    NextScan
EndProg

Remarks

The CS7500 instruction is used to communicate with the LI-7500(A) via ClosedSDM Synchronous Device for Measurement. A processor-based peripheral device or sensor that communicates with the datalogger via hardwire over a short distance using a protocol proprietary to Campbell Scientific..

Parameters

Dest (Destination)

The Variable in which to store the results of the instruction. Right-click the parameter to display a list of defined variables.

If this instruction has a Repetitions parameter and it is greater than 1, the results are stored in an array with the variable name. The array must be dimensioned large enough to hold all of the values returned from all of the Reps.

Type: Variable or Array

For the CS7500 instruction, the Dest parameter is the input variable name in which to store the data from each gas analyzer associated with this instruction. The length of the input variable array will depend on the number of repetitions and on the selected command.

Command Input Variable Length
per Gas Analyzer
0 and 1 2
2 4
3 3
4 11
5 3
6 4

Reps (Repetitions)

The number of repetitions for the measurement or instruction.

Type: Constant integer (or expression that evaluates as a constant).

For the CS7500 instruction, the Reps parameter determines the number of gas analyzers with which to communicate using this instruction. The devices must have sequential ClosedSDM Synchronous Device for Measurement. A processor-based peripheral device or sensor that communicates with the datalogger via hardwire over a short distance using a protocol proprietary to Campbell Scientific. addresses if the Reps parameter is greater than 1.

SDMAddress (Address of Device)

Defines the address of the device with which to communicate. Valid ClosedSDM Synchronous Device for Measurement. A processor-based peripheral device or sensor that communicates with the datalogger via hardwire over a short distance using a protocol proprietary to Campbell Scientific. addresses are 0 through 14. Address 15 is reserved for the SDMTrigger instruction.

Some SDM instructions support repetitions. If a Reps parameter is present and it is greater than 1, the data logger will increment the SDM address used in the instruction for each subsequent device with which it communicates.

CS7500Cmd (Data to Retrieve)

Requests the data to retrieve from the sensor. The command is sent first to the device specified by the SDMAddress parameter. If the Reps parameter is greater than 1, subsequent devices will be issued the command with each rep. The results for the command will be returned in the array specified by the Dest parameter. A numeric code is entered to request the data. Right click the parameter to display a drop-down list box.

Code Description
0 Get CO2 & H2O molar density (mmol/m^3).
1 Get CO2 & H2O absorptance.
2 Get pressure (kPa), temperature (C), auxiliary measurement 1, and cooler voltage (V).
3 Get cell diagnostic value, output bandwidth (Hz), and programmed delay.
4 Get CO2 molar density (mmol/m^3), H2O molar density (mmol/m^3), CO2 absorptance, H2O absorptance, pressure (kPa), temperature (C), auxiliary measurement 1, cooler voltage (V), diagnostic value, output bandwidth (Hz), and programmed delay.
5 Get CO2 & H2O molar density (mmol/m^3) and pressure (kPa).
6 Get CO2 and H2O molar density (mmol/m^3), pressure (kPa), and diagnostic.