Campbell HMP 35A Manuel d'instructions télécharger pdf (Page 30)

Appendix B. Example Programs

B.2 Differential Measurement Example

Below is an example CR1000 program that uses the differential voltage

instruction to measure the sensor and uses the datalogger’s SW12V terminal to

power the sensor only when it is being measured. The differential instruction

is recommended for long lead lengths. TABLE B-2 shows the wiring used for

these examples.

Other CRBasic dataloggers are programmed similarly.

TABLE B-2. Wiring for

Differential Measurement Examples

Color Description CR1000

Yellow Temperature 2H

Jumper to 1L 2L

Blue Relative Humidity 1H

White Signal Reference 1L

Red Power SW12 V

Black Power Ground G

Clear Shield

'CR1000 program to measure HMP155A with differential measurements

Public AirTC

Public RH

DataTable(Temp_RH,True,-1)

DataInterval(0,60,Min,0)

Average(1,AirTC,IEEE4,0)

Sample(1,RH,IEEE4)

EndTable

BeginProg

Scan(5,Sec,1,0)

'HMP155A Temperature & Relative Humidity Sensor measurements AirTC and RH:

PortSet (9,1)

Delay(0,2,Sec)

VoltDiff (AirTC,1,mV2500,2,True,0,_60Hz,.14,-80)

VoltDiff (RH,1,mV2500,1,True,0,_60Hz,0.1,0)

PortSet (9,0)

If RH>100 And RH<108 Then RH=100

CallTable(Temp_RH)

NextScan

EndProg

B-2

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Campbell HMP 35A Manuel d'instructions Page 30