Operator`s manual

Signametrics 14
2.9 Timing Measurements (SM2042, SM2044)
2.9.1 Threshold DAC
• The Threshold DAC is used for selecting a detection threshold to give optimal frequency and
timing measurements.
± (% of setting + volts)
Selected VAC
range [1]
Threshold range (DC
level)
Threshold
DAC
resolution
Highest allowed input
Vp-p
Typical one year setting
uncertainty
330 mV -1.0 V to +1.0 V 0.5 mV 1.900 V 0.2% + 4 mV
3.3 V -10.0 V to +10.0 V 5.0 mV 19.00 V 0.2% + 40 mV
33 V -100.0 V to 100.0 V 50 mV 190.0 V 0.2% + 0.4 V
250 V -500 V to 500 V 500 V 850.0 V 0.2% + 4 V
[1] This table should be used in conjunction with the AC volts section above.
2.9.2 Frequency and Period Measurement
ACV Mode
• Input Impedance 1 MΩ with < 300 pF
Frequency Range 1 Hz - 100 Hz 100 Hz-1 kHz 1 kHz-10 kHz 10 kHz-100 kHz 100 kHz-300 kHz
Resolution 1 mHz 10 mHz 100 mHz 1 Hz 1 Hz
Uncertainty is ±0.002% of
reading ± adder shown
4 mHz 20 mHz 200 mHz 2 Hz 5 Hz
Input Signal Range [1] 10% - 200%
of range
10% - 200%
of range
10% -200%
of range
10% - 200%
of range
45% -200%
of range
[1] Input RMS voltage required for a valid reading. Do not exceed 250 V RMS input. For example, 10% -200%
of range indicates that in the 330 mVAC range, the input voltage should be 33 mV to 660 mV RMS.
ACI Mode
• Input Impedance 10 Ω in the 3 mA and 30 mA ranges, 0.1 Ω in the 330 mA and 2.5 A ranges.
Frequency Range 1 Hz - 100 Hz 100 Hz-1 kHz 1 kHz-10 kHz 10 kHz-500 kHz
Resolution 1 mHz 10 mHz 100 mHz 1 Hz
Uncertainty 0.01% ±4 mHz 0.01% ±20 mHz 0.01% ±200 mHz 0.01% ±2 Hz
Input Signal Range,
3.3 mA, 330mA Ranges
[1]
10% -500%
of range
10% - 500%
of range
10% -500%
of range
10% - 500%
of range
Input Signal Range,
33 mA, 2.5A ranges
50% -100%
of range
50% - 100%
of range
50% - 100%
of range
50% - 100%
of range
[1] Input current required to give a valid reading. For example, 10% -500% of range indicates that in the 3.3 mA
range, the input current should be 0.33 mA to 16.5 mA.
2.9.3 Duty Cycle Measurement
Frequency Range 1 Hz to 100 Hz 100 Hz to 1 kHz 1 kHz to 10 kHz 10 kHz to 100 kHz
Resolution 0.02% 0.2% 2% 20%
Typical Uncertainty is
±0.03% of reading ±
adder shown
0.03% 0.3% 3% 20%
Full scale reading 100.00 % 100.00 % 100.00 % 100.00 %