149
Signametrics
6.9 Frequency Counter Test ( SM2064 only)
The following procedure may be used to verify the accuracy of the Frequency Counter:
1. If you have not done so, install the DMM 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. Select the ACV function, autorange. Turn
freq
on.
3. Apply the following AC voltages to the
V,
Ω
+ & -
terminals. Check to see that the displayed reading on the
SM2064 is within the indicated range of readings.
ACV Frequency Counter Test
Step
Range
Input
Minimum Reading
Maximum reading
1
240 mV
33 mV, 40 Hz
39.9952 Hz
40.0048 Hz
2
2.4 V
240 mV, 40 Hz
39.9952 Hz
40.0048 Hz
3
24 V
2.4 V, 40 Hz
39.9952 Hz
40.0048 Hz
4
330 V
24 V, 40 Hz
39.9952 Hz
40.0048 Hz
5
240 mV
250 mV, 100 kHz
99.996 kHz
100.004 kHz
6
24 V
25 V, 100 kHz
99.996 kHz
100.004 kHz
U
For ACI Frequency Counter test:
1. If you have not done so, install the DMM 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. Select the ACI function, autorange. Turn
freq
on.
3. Apply the following AC currents to the
I,4
Ω
+ & -
terminals. Check to see that the displayed reading on the
DMM is within the tolerance appropriate for your application (e.g. 90 day or 1 year accuracy).
ACI Frequency Counter Test
Step
Range
Input
Counter Reading
Tolerance
1
3.3 mA
330 uA, 40 Hz
2
33 mA
15 mA, 40 Hz
3
330 mA
150 mA, 40 Hz