Example:

A 10 volt, full-scale voltmeter is calibrated at the full-scale

point (figure 8). The meter has a manufacturer's tolerance of 3% of FS. A

variable voltage source is connected to the meter (TI) and adjusted to cause

the TI to read exactly 10 volts. A standard meter is also connected to the

voltage source and reads the true value, 10.4 volts; therefore, r=10 volts,

a=0.4 volt, and e=4% of FS. The TI is out of the 3 percent tolerance and

requires adjustment.

Figure 8.

Out of Tolerance Condition

c. The alternate method is to set the standard to an exact value or use

a single-value standard.

The standard is monitored by the TI.

Error is

calculated as above, with the TI reading still considered r.

Figure 9.

Micrometer Measurement

A micrometer with A range of 0 to 1 inch is calibrated at full

scale (figure

9). A 1 inch gage block is used as a standard (consider the

block exactly

0.001 inch;

1.000 inch).

The allowable error tolerance of the TI is

therefore, the TI is within tolerance. The percentage error

of the TI was

0.001/1.001 x 100 or -0.099%.

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