ProMinent Aegis-II, Руководство по сборке и эксплуатации, Страница: 80 / 102

Programming the Outputs
Page 80 of 102
The Sample time should be set for a long enough
period that ensures a fresh sample has passed the
sensor.
The Measure time is 60 seconds. This cool down
period increases accuracy of the reading as well as
adding to the life of the probe. Typically, this value is
not adjusted.
Blowdown defaults to 120 seconds, a good starting
point.
Resample is the wait time between sample cycles.
After the resample time has elapsed, the valve
opens and takes a new sample to start over.
Basic operation:
At the start of a captured sample routine, the
blowdown valve opens for the
Sample
period. The
pipe at the sensor should be hot before the valve
closes.
The
Measure
stage holds the valve closed for 1
minute to cool the sample and get a steady reading.
The controller uses the sensor value at the end of
the measure period. This sensor reading is
converted to a conductivity value and compared with
the set-points. If too high, a blowdown step is
started. If below the turn off set-point, the blowdown
step is skipped.
The
Blowdown
valve is now opened for the set time
and closed. A second measure time is started,
allowing the sample to cool as before, read the
sensor and compare it to the set-points. As long as it
is above the turn off point, the controller will oscillate
between the measure and blowdown steps.
Once the conductivity low level is reached, the
Resample
timer holds the valve closed until the
next cycle starts.
NOTICE:
If the routine is not keeping the boiler conductivity
within the preferred range, consider these
adjustments;
Conductivity rises: 1) If the conductivity rises too
much between samples, decrease the resample
delay time (Run the routine more often).
2) If the measure/blowdown steps are repeating
without stop, lengthen the blowdown time or open
the restriction to allow more flow.
Remember, opening the restriction moves you closer
to losing control of the flashing. Adjust in small
amounts and monitor 2 or 3 cycles before approving
the change.
Figure 62 Boiler Blowdown Diagram