Campbell Scientific CR1000 Measurement and Control System - Manual (Page 37)

Section 4. Quickstart Tutorial
37
Table 1. Single-Ended and Differential Input
Channels
Differential Channel Single-Ended Channel
1H 1
1L 2
2H 3
2L 4
3H 5
3L 6
4H 7
4L 8
5H 9
5L 10
6H 11
6L 12
7H 13
7L 14
8H 15
8L 16
4.1.3.2 Bridge Sensors
Many sensors use a resistive bridge to measure phenomena. Pressure sensors and
position sensors commonly use a resistive bridge. Examples:
• A specific resistance in a pressure transducer strain gage correlates to a
specific water pressure.
• A change in resistance in a wind vane potentiometer correlates to a change in
wind direction.
4.1.3.2.1 Voltage Excitation
Bridge resistance is determined by measuring the difference between a known
voltage applied to a bridge and the measured return voltage. The CR1000
supplies a precise scalable voltage excitation via excitation terminals. Return
voltage is measured on analog terminals. Examples of bridge sensor wiring using
voltage excitation are illustrated in figures Half-Bridge Wiring -- Wind Vane
Potentiometer
(p. 38)
and Full-Bridge Wiring -- Pressure Transducer
(p. 38).