Campbell OXYGUARD TYPE III CS512 User Manual download pdf (Page 10)

Campbell Scientific CS512 Oxyguard Type III Dissolved Oxygen Probe

8. Calibration

The multiplier is used to calibrate the CS512 probe. To calculate the multiplier:

1) Program the datalogger using a multiplier of one.

2) Place the OxyGuard probe in the air, shaded from the sun. Wait for readings

to stabilize. This may take 15 minutes or more.

3) Determine the air temperature and barometric pressure.

4) Using a calibration chart such as that provided in the probe’s manual,

determine the oxygen concentration of the air.

5) Use the following equation to calculate the multiplier:

M = P/R

M = Multiplier

P = Concentration in PPM of the air (from the calibration chart in Appendix A)

R = The signal output of the OxyGuard probe when using a multiplier of one

6) Change the multiplier in the datalogger program from one to the calculated

number.

A more common way to enter the multiplier is to insert a separate instruction in

the program. This will allow a new multiplier to be added to the program

without rewriting, compiling, and downloading the program to the data logger.

In the CR510, CR10X, and CR23X, use Instruction P36. The multiplier is

entered into an input location called DOmult using the numeric display in

PC200W, PC208W, LoggerNet, PC400, PConnect, PConnectCE, or the

CR10KD.

EXAMPLE 6. Sample Program using P36

57: Z=X*Y (P36)

1: 1 X Loc [ DOmV ]

2: 2 Y Loc [ DOmult ]

3: 3 Z Loc [ DOppm ]

In all dataloggers that use CRBasic, an expression is written. The multiplier

value is entered into the expression through the Public Table using the numeric

display in PC200W, LoggerNet, PC400, PConnect, and PConnectCE.

EXAMPLE 7. Sample Program using Expression

DOppm = DOMult * DOmV

1 2 ... 5 6 7 8 9 10 11 12 13 14 15 16

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Campbell OXYGUARD TYPE III CS512 User Manual Page 10