Seametrics EX100-200 Series v.2 - Manual (Page 14)

OPERATION & MAINTENANCE
Page 12
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 silver bumps) on the reading face of the
flow sensor. A mild soap (dishwashing liquid for example)
can be used to aid the cleaning process.
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” on
page 13. These numbers are based on extensive testing,
which has shown close agreement between different EX
sensors in the same installation. Typically, most K-factor
error can be attributed to installation variables, such as
depth setting and fitting configuration.
To perform the adjustment, after determining that there is
a full pipe with no flow, short between the two pins marked
“Zero Adjust”. A red LED light will come on for approxi-
mately 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 13 for the minimum flow rate
detectable by the sensor (at 0.2 ft/sec) for a given pipe
size.
Presence of Flow Indication. To assist in troubleshooting,
the “Status LED” has two blinking modes in normal
operation. When there is no flow detectable by the meter
(below minimum threshold) the LED blinks ever y 8.0
seconds. When there is detectable flow, the same indicator
blinks every 3.0 seconds.
Filtering. The software of the EX100/200 Series filters
out electrical noise and 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.
Zero Adjustment. When the EX100/200 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 it may be necessary to adjust
the flow meter under no-flow conditions after it has been
installed. This should only be done if the indicated flow is
low, near the lower cutoff.
30
Vdc
Max. 6m
A
- + - +
12-24
Vd
c
3 4 5 6 2 1
Power Forward
Output
Status
LED
Zero
Adjust
Pins
Zero
Adjust
Pins
Status
LED
AR
CH
IVE
D
(Includes Dates 5/05 to 9/06)