Seametrics EX100-200 Series v.1 - Manual (Page 12)

OPERATION & MAINTENANCE
Page 10
Calibration (“K-Factor”). In order to properly process
pulses from the flow sensor, a number must be entered
into the control to which the sensor is connected. This
number, called the K-factor, is the number of pulses the
sensor puts out per unit of fluid passing through the pipe.
It is normally provided for SeaMetrics sensors in pulses
per gallon, and is given on the chart “K-factors for Various
Pipe Sizes.” These numbers are based on extensive test-
ing, which has shown close agreement between different
EX sensors in the same installation. Typically, most K-fac-
tor error can be attributed to installation variables, such
as depth setting and fitting configuration.
When the EX100 Series Meter is powered up and there is
no flow, there should be no output pulses (or, if connected
to the FT420, flow rate should read “0”). If there are
pulses...
Zero Adjustment. In some cases it may be necessary
to adjust the flow meter under no-flow conditions after it
has been installed.
To per form the adjustment, after determining that there is
no flow, shor t between the two pins marked “Zero Adj.” A
red LED light will come on for approximately 50 seconds
and then go out. The zero adjustment is completed.
Minimum Flow. As with any other flow sensor, there is a
rate below which the EX100 Series sensor cannot read.
Check the the table on page 11 for the minimum flow rate
detectable by the sensor (0.2) for a given pipe size.
Filtering. The software of the EX100 Series sensor filters
out electrical noise and also averages sudden variations
in the flow to smooth the output. It takes a matter of
seconds for the flow sensor to get up to full output when it
is powered up or when flow begins. If the unit responds
ver y slowly, it is probably due to excessive electrical noise.
If this is the case, check for adequate grounding to improve
the response.
Electrode Coating. Grease or other adhering, non-
conductive materials can stop flow detection if the
electrodes become heavily coated. To clean the electrodes,
remove the sensor from the pipe and gently scrub the
electrodes (three dark grey bumps) on the reading face of
the flow sensor. A mild soap (dishwashing liquid for
example) can be used to aid the cleaning process.
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(Includes Dates Before 5/05)