Campbell AVW1 Spécifications télécharger pdf (Page 20)

AM16/32B Relay Analog Multiplexer

Delay (0,20,mSec)

Portset (2,0) ‘Set port 2 low

INCREMENT INDEX AND MEASURE

I=I+1

'User specified measurement instruction

‘Storing results in Variable(I)

END MEASUREMENT LOOP

NextSubScan

DEACTIVATE MULTIPLEXER

Portset (1 ,0) 'Set C1 Low to disable Multiplexer

In addition to precision voltage excitation, the CR5000 and CR3000 have

programmable current excitation. Current excitation allows a resistance

measurement on a four-wire sensor (e.g., a PRT) such as shown in Figure 15

using only a single differential channel and no fixed resistor; the excitation

return goes directly to ground. With the current excitation the resistance of the

relays and lead wire do not affect the measurement.

5.1.1 CR1000, CR800, and CR850 Programming

Although the following example is a CR1000 program, a similar program can

be used for the CR800 or CR850. This CR1000 program uses the AM16/32B

to measure 48 CS616 probes connected in the 4x16 configuration. The

program also measures datalogger battery voltage and temperature.

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Campbell AVW1 Spécifications Page 20