| 摘要 |
PURPOSE: To provide a highly precise weighing equipment at a low cost by installing a third voltage different from an electric power source voltage and a standard voltage and dividing the voltage obtained by amplification of the output of a strain gauge attached to a load cell and the third voltage with a temperature sensing resistor and a normal resistor. CONSTITUTION: A third voltage VP different from an electric power source voltage VDD and a standard voltage VSS is installed and the output VX obtained by dividing the voltage V1 obtained by amplifying the output of a strain gauge attached to a load cell and the third voltage VP with a temperature sensing resistor R3 and a normal resistor R4 is connected with an A/D converter. The output VX can be expressed as VX=R4 /(R4 +R3 )×(V1 +VP)+VP in the case where the temperature sensing resistor R3 is set in this way. If VP is so set as to satisfy V1 =VP, VX becomes equal to VP and is constant independently of the R3 value. That is, it is indicated that an indicated value does not fluctuate even if temperature alters in a no load state by setting VP=V1 ,0 while the amplified output V1 in no load state being set to be V1 ,0 .
|
