User manual

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MC-III™ EXP Flow Analyzer Section 4
Rate Display
The Rate display comprises two parts: a volume unit and a time-base unit. The volume portion of the Rate
display can be congured in one of ve preprogrammed engineering units or in a user-dened unit (for use
with a calculated divisor). To display the volume portion in multiples of 1,000 units, check the “Multiplier”
checkbox.
The time-base portion of the Rate display can be congured in one of four preprogrammed engineering units:
per day, per hour, per minute, or per second. Users can specify decimal point position, from no decimal up to
0.001 of a unit, using the slide bar on the Turbine Input screen.
Important: If the volume portion of the Rate display is to be measured in user-dened units, the
K-Factor unit must also be entered as “pulses per unit.” For more information, see Enter-
ing a Calculated Divisor, page 37.
Caution: An overrun error occurs when the number of digits in the ow rate value exceeds the
display capacity of the device. To clear this error, reduce the number of decimal places
(for example, display rate in tenths rather than hundredths), or enable the “× 1000” unit
setting for the rate display using the “Multiplier” checkbox described above to display
rate in terms of thousands of units.
Figure 4.22—Overrun error
Input Type and Sensitivity Conguration
The MC-III EXP accepts either a turbine input or a pulse input. When the turbine input is selected, the user
can also specify one of three sensitivity levels (low, medium, or high) to help minimize noise interference in
the signal reception. A “low” sensitivity setting will detect a signal of approximately 20 mV peak-to-peak,
while a “high” sensitivity setting will detect only signals that exceed 40 mV, peak-to-peak.
When a pulse input is selected, no sensitivity setting is required.
Cut-Off Thresholds
Periods of very low or interrupted ow can lead to inaccuracies in indicated ow totals. To help prevent these
inaccuracies, the user can establish cut-off thresholds to determine the minimum frequency and/or ow rate at
which a signal will be recorded.
The ow rate cut-off is a setpoint for the accumulation of ow time in the hourly and daily records, and can
be applied to either a turbine input or pulse input.
The frequency cut-off is reserved for the turbine input only. When the low-frequency cut-off is congured, the
MC-III EXP will ignore inputs that are less than the user-entered value.
Calculation Period
The ow calculation period is the number of seconds that are allowed for calculating the ow condition. This
setting is easily adjusted with the “plus” and “minus” buttons on the screen, or the page-up and page-down
keys on your computer keyboard. Increasing this setting value results in ow rates with greater resolution.
This setting is also the time allowed for processing of display updates.