22
Limits
The limit screen is used to set the parameters that
trigger the outputs. To use this function, set the
Input Source on the Output Settings menu to Limit.
The limit has 4 types of triggers: Rate, Total, Grand
Total, and Cycle Output.
Rate
– Output will go high when flow rate is within
the given parameters and low when it goes outside.
Select a threshold/ target rate, then select the
percentage the flow rate that is allowed to drift
from that threshold. Example: a 10% bound on a
threshold of 20 gpm would give a rate range of 18-
22 gpm.
Total
– Output will go high when Total goes above
the threshold value.
Grand Total
- Output will go high when Grand
Total goes above threshold value.
Cycle Output
– Output will change state between
high and low every time the threshold total is
reached. To achieve one pulse per desired output,
divide that value by 2. For example, to get 1 pulse
per gallon set threshold to 0.5 gallons.
*Cycle Output limited to 5Hz or 300 pulses per minute*
Linearizer
The linearizer function is designed to correct for
devices that will vary in a nonlinear way as a device
changes in flow/frequency. It can take nonlinear
input and change it to a more linear analog output.
(Figure 14)
Ex. Looking at a meter that has a range of 0.5-2 GPM.
If at 0.5 GPM (=100HZ) it has a K-factor of 1800, at 1.5
GPM (=200Hz) it has a K-factor of 1850, and at 2.0 GPM
(=300Hz) it has a K-factor of 1900. Using a linearizer
would ensure the most accurate results over the full
range of flow.
Figure 13: Limits
Figure 14: Linearizer
Table
Summary of Contents for FPD-4000 Series
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