PLATINUM
TM
Series Controllers User
’s
Guide
M5451
Omega Engineering | www.omega.com
32
Reference Section: Initialization Mode (INIt)
6.1.4.2
Bridge Inputs
Ratiometric inputs are widely used for bridge inputs as found in load cell and pressure sensors because
any fluctuations in the excitation voltage are eliminated in the final reading.
The input is configured as a ratiometric input, where the voltage difference between terminals 2 (AIN+)
and 3 (AIN-) is measured with respect to the externally applied voltage reference applied between
terminal 1 (ARTN) and terminal 4 (APWR).
The Excitation voltage, set to 5 or 10 Vdc is used to power the external bridge sensor. Two external
resistors provide a divider circuit to ensure that the differential inputs are biased at ½ of the voltage
generated by the on-board Excitation Voltage.
Resistors (R1, R2): ~ 4.7 k ohms.
NOTE: An
internal
2.0 k ohms resistor is connected between terminal 1 (ARTN) and terminal 4
(APWR).
Bridge Element
1
2
3
4
5
6
7
8
9
10
R1
R2
