Specifications

Section 11. Programming Resource Library

11-5

BeginProg

Multiplier = .05

Offset = 0

KnownRH = 0

LoadFieldCal(true) 'Load the CAL File, if possible

Scan(100,mSec,0,0)

'Simulate measurement by exciting channel Vx/EX1

ExciteV(Vx1,mV,0)

'Make the calibrated measurement

VoltSE(RH,1,mV2500,8,1,0,250,Multiplier,Offset)

'Perform a calibration if CalMode = 1

FieldCal(0,RH,1,Multiplier,Offset,CalMode,KnownRH,1,30)

'If there was a calibration, store it into a data table

CallTable(CalHist)

NextScan

EndProg

11.1.5.2 Offset (Option 1)

Case: A sensor measures the salinity of water. Multiplier is known to be

stable, but sensor offset drifts and requires regular offset correction using a

standard solution. The following procedure offsets the measurement to obtain

the calibration report shown.

Calibration Report for Salinity Sensor

Initial Calibration 1 week Calibration

mV Output 1350 mV 1345 mV

Standard Solution 30 mg/l 30 mg/l

Multiplier .05 mg/l/mV .05 mg/l/mV

Offset -37.50 mg/l -37.23 mg/l

Reading 30 mg/l 30 mg/l

Send the program in EXAMPLE 11.1-2 to the CR1000. Put a jumper wire

etween channels Vx/EX1 and SE8 (4L).

Using the CR1000KD keyboard or software numeric monitor, change the value

in variable CalibMode to 1 to start calibration. When CalibMode increments to

6, the calibration is complete.