MicroStrain, Inc.
15
Connecting a quarter bridge strain gauge
This example assumes the SG-Link® OEM is configured with the optional internal
quarter
bridge completion resistors. If not, the completion of the bridge (shown as
internal circuitry) must be completed externally. The three wire arrangement is
recommended in order to cancel thermal effects of the lead wire resistance (RL).
It is
strongly recommended that shielded wiring be used, as this can significantly reduce
system noise.
Please note that the shield of each cable must be grounded at one location
only, to prevent the occurrence of ground loops. Shielded wiring can be purchased from
Alphawire (part number 1122,
www.alphawire.com
); a sample is included with each
starter kit.
Figure 2
Sensor-
Sensor Sense
Ground Pin
S+ (Pin 2)
Sense (Pin 5)
GND (Pin 4)
Table 4
S+
S-
S-
Sensor -
Sensor Sense
Sensor Ground
Ground
Sensor Power
Sense
Rg
Rg
RL*
RL*
Rg
RL*
Rg
(Active)
Shield
(Drain)
Internal Circuitry
*RL=Lead Resistance
