
Generally, the choice of gate time is a matter of factoring the desired resolution against the time the
actual measurement takes.
Multiple Channels:
When scanning over multiple channels, the software must explicitly select the next channel in the scan
and start a new conversion. Once the next channel is selected, enough time must be allowed for the new
channel’s current to propagate through the multiplexers and Current-to-Voltage Converter to settle at the
Voltage-to-Frequency converter input. T his is most easily done by doing an extra, or ‘dummy’
conversion, waiting for it to complete and then starting the ‘real’ conversion. Thus, if a gate time of
0.0166 seconds is chosen, the maximum scan rate will be:
Scan Rate = 1 / 2 x [gate time]
= 1 / 2 x [0.0166 seconds]
= 30 samples per second
The following table can be used to select the Gate Count based on either desired maximum sampling rate
or desired resolution.
400Hz0.1 °C0.0025 sec5,000200 samples / sec
50Hz0.0125 °C0.02 sec40,00025 samples / sec
60Hz0.015 °C0.01 sec33,33330 samples / sec
Line Frequency
Rejection
ResolutionGate TimeGate Count
Required
Desire Max Sample
Rate
8
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