7088-8000
-158
Minimum and Maximum Flow Range Values
The minimum and maximum values can be set for the volumetric flow range. Setting the
optimum flow range generally improves the flowmeter’s response time.
NOTE:
Whenever the pipe ID is changed, the flowmeter returns the volumetric flow
range to its default settings. The default settings are the minimum and maximum
flows for the new pipe ID that occur at +32 and -32 FPS (+9.76 and -9.76 MPS).
To set the minimum and maximum values for the flow range:
1. From the
FLOW
options group, click on the
MIN FLOW
text box.
2. Enter the minimum value for the flow range.
3. Click on the
MAX FLOW
text box.
4. Enter the maximum value for the flow range.
Damping
The damping coefficient suppresses short term fluctuations in the indicated flow rate. The
displayed flow rate and the 4 to 20 mA current loop output is a moving average of the last
n seconds where n is the damping value. Increasing the coefficient increases the response
time to changes. The coefficient is adjustable from 1 to 99 seconds in 1-second increments.
Damping should be kept at a minimum unless the velocity fluctuates wildly. If so, damping
should be increased just enough to reduce the fluctuation to an acceptable degree.
To set the damping:
1. From the
FLOW
options group, click on the
DAMPING
text box.
2. Enter the damping value.
Cutoffs
The flowmeter can be configured with a low signal cutoff or a low flow (low velocity)
cutoff. The cutoff function which is selected (low flow, low signal, or both) and the
accompanying cutoff value should be based on the specifics of the application.
Experimentation is recommended for achieving optimum results.
Low Flow Cutoff
When a zero flow condition occurs (for example, as the result of a pump being shut off),
internal sloshing, check valve leakage, and other fluid movement can prevent the
flowmeter from reading total zero. This phenomenon can result in totalizer errors. These
errors can be minimized by entering a low flow cutoff (a minimum acceptable value for
flow). Setting a low flow cutoff drives the flowmeter to zero for flow rates at or below that
value. If the flow rate (regardless of direction) falls below the low flow cutoff value, the
instrument’s indicated flow is driven to zero and the totalizers stop incrementing.
To Next Page
Loading...
Need help?
General