Specifications

Procedure The leadwire resistance is determined with the following parameters:

• the voltage across the lower leg 1kΩ internal half bridge resistor

(V_lower)

• the bridge output voltage (Vout)

• the voltage across the leadwire (V_leadwire)

• the 120Ω or 350Ω bridge completion resistor (Rcomp).

These parameters are represented with the circuit of Figure C-2 and the

leadwire resistance is calculated using the equation:

R_leadwire = (V_leadwire x Rcomp)/(V_lower + Vout - V_leadwire)

Figure C-1. Externally Supplied Bridge Excitation Voltage

Figure C-2. Determining Leadwire Resistance

Appendix C Strain Gage Diagnostics 109

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