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2.3.5 Step 5 - Sampler
Pacing
2.3.6 Step 6 - Sampler
Enable
It is common to use a flow meter with an Isco Automatic Waste-
water Sampler. Typically, the flow meter signals the sampler to
take a sample after a certain volume has passed. It might also
occur after a certain condition or set of conditions has either
changed or been met. This step allows you to determine that
control. There are several possible options—DISABLE, CONDI-
TIONAL, VOLUME, and FLOWLINK. DISABLE will keep the
sampler from receiving a flow pulse from the flow meter.
VOLUME allows the flow meter to signal the sampler whenever
a specific flow volume has passed by. Flowlink (this option will
only appear if you are using Flowlink software) allows the
sampler to be signalled from the flow meter as a result of condi-
tions determined by Flowlink.
Flowlink is Teledyne Isco's proprietary data acquisition and
management software. Flowlink works with personal computers,
modems, and laptop computers to monitor flow meters from a
distance. Consult the factory for more details about Flowlink.
VOLUME makes the flow meter pace the sampler after a spe-
cific volume passes through the stream.
CONDITIONAL allows pacing of the sampler by the flow meter
when a particular condition has been met, or has changed.
Among these conditions are changes in level, flow rate, temper-
ature, rainfall, (if you are using the optional rain gauge sensor),
D.O. (dissolved oxygen), or pH. You can also use a pair of condi-
tions, or if you are using the YSI 600 sonde, you can select mul-
tiple conditions from its sensors.
Note
If you choose CONDITIONAL for sampler pacing and it doesn't
seem to work properly for you, read the section on hysteresis.
Then check the hysteresis setpoints for your conditions. (The
defaults are all zero.)
You must have the appropriate sensors attached to the flow
meter to measure temperature, D.O., pH, conductivity, etc.; the
flow meter cannot do this by itself, nor does it occur automati-
cally.
S a m p l e r E n a b l e m e a n s t h a t i n a c o m b i n a t i o n f l o w
meter/sampler pair, the flow meter controls the sampler's ability
to run its own program. The difference between step 5, sampler
pacing, and step 6, sampler enable, is that in sampler pacing,
the flow meter merely sends flow pulses to the sampler from time
to time. The sampler counts these flow pulses to determine when
to take a sample (according to its own programming).
With sampler pacing, the sampler is always enabled. With
sampler enabling, the flow meter can actually stop operation of
the sampler. The sampler is still set up to run its own program,
but the inhibit/enable line from the flow meter will determine
when and whether the sampler runs its program. This feature is
useful for storm water runoff monitoring applications, where it
may be necessary for the flow meter/sampler pair to have to wait
a long time between storm intervals.
4250 Flow Meter
Section 2 Programming
2-9
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Troubleshooting
