Campbell-scientific HMP155A Temperature and Relative Humidity Probe Manuel d'utilisateur télécharger pdf (Page 31)

Appendix B. Example Programs

B.2 Differential Measurement Examples

These examples use the differential voltage instruction to measure the sensor

and use 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.

TABLE B-2. Wiring for

Differential Measurement Examples

Color Description CR1000 CR10(X)

Yellow Temperature 2H 2H

Jumper to 1L 2L 2L

Blue Relative Humidity 1H 1H

White Signal Reference 1L 1L

Jumper from SW12V Control C1

Red Power SW12 V SW12 V

Black Power Ground G G

Clear Shield

B.2.1 CRBasic Differential Measurement Program

Below is an example CR1000 program. Other CRBasic dataloggers are

programmed similarly.

'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-3

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Campbell-scientific HMP155A Temperature and Relative Humidity Probe Manuel d'utilisateur Page 31