Operator`s manual

Signametrics 114
6.0 Maintenance
Warning
These service instructions are for use by qualified personnel only. To avoid electric shock, do not perform
any procedures in this section unless you are qualified to do so.
This section presents maintenance information for the DMM.
Test equipment recommended for calibration is listed below. If the recommended equipment is not available,
equipment that meets the indicated minimum specifications may be substituted. In general, the calibration
equipment should be at least three times more accurate than the DMM specifications.
Table 9-1. Recommended Test Equipment
Instrument Type Minimum Specifications Recommended Model
Multi-Function Calibrator
DC Voltage Range: 0-300 V
Voltage Accuracy: 9 ppm
AC Voltage Range: 0-250 V
Voltage Accuracy: 0.014%
Resistance Range: 0-330 MΩ
Resistance Accuracy: 22 ppm
DC Current Range: 0-2.5 A
Current Accuracy: 0.008%
AC Current Range: 50 uA – 2.5 A
Current Accuracy: 0.05%
Capacitance Range: 10 ηF – 10 mF
Capacitance Accuracy: 0.19%
Fluke 5520A
6.1 Performance Tests
This test compares the performance of the SM2040 with the specifications given in Section 2. The test is
recommended as an acceptance test when the instrument is first received, and as a verification after performing the
calibration procedure. To ensure proper performance, the test must be performed with the SM2040 installed in a
personal computer, with the covers on. The ambient temperature must be between 18°C to 28°C. Allow the
SM2040 to warm up at least one-half hour before performing any of the tests. The default reading rate of the
SM2040 should be used in each test.
6.2 DC Voltage Test
The following procedure may be used to verify the accuracy of the DCV function:
1. If you have not done so, install the SM2040 and place the covers back on to the computer. Ensure that the
computer has been on for at least one-half hour, with the covers on, before conducting this test.
2. Apply a high quality copper wire short to the SM2040 V,Ω + & - inputs. Select the DCV function, Autorange.
Allow the SM2040 to settle for several seconds, and perform the Relative function.
3. Apply the following DC voltages to the V, Ω + & - terminals. Check to see that the displayed reading on the
SM2040 is within the indicated range.