Mace HydroMace XCi, Руководство по эксплуатации продукта, Страница: 224 / 270

Calibrate - Flowrate (using pulse) function
The MACE FloSeries3 Pulse card is used to calculate a flow rate based upon the number of pulses received
over a period of time. The Pulse card " K-factor ", scales the pulses to the required flow rate units.
There are two ways to do this:
l
If you have a pulsing flow meter with a published pulse output, you can calculate a "
K-factor
".
l
If you have a pulsing flow meter with an unknown "
K-factor
", you can use the "
Calibrate
" function to
calculate it for you.
NOTE: A MACE FloSeries3 Pulse card should not be used for "counting" "totaliser
pulses. For that application, a MACE FloSeries3 I/O card should be used with an
" Add a new "Input pulse total" channel type ".
Calculate a "K-factor"
Metric Example:
Most pulsing flow meters, output a
known number of pulses per unit volume
. For example, an insertion-style
electromagnetic flowmeter, may output say 5.36 pulses/litre in a DN150 pipe. These pulses do not constitute
a "
Flow rate
" since all we know, is how many pulses are sent for a litre of liquid that passes through the pipe
(5.36). To make these pulses a flow rate, they must be counted over a period of time and multiplied by a "
K-
factor
" to give
volume per unit time
.
The"known" " meter pulses/unit volume " must be converted to the required flow rate units and timebase
for use by the FloSeries3 Pulse card, using the following method:
1. The meter k-factor is published as pulses per unit volume (eg. pulses per litre). This must be converted
to unit volume per pulse by inverting the published k-factor.
1 ÷ 5.36 = 0.18636 litres per pulse
2. Convert the inverted k-factor to the correct timebase to be used in the flow rate calculation.
l
Multiply by 1 for seconds
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Multiply by 60 for minutes
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Multiply by 3600 for hours
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Multiply by 86400 for days
eg. If the required flow rate units are in L/hr (litres per hour) multiply the inverted k-factor by 3600
0.18636 x 3600 = 670.896
MACE XCi User Manual - 224 -