14
3. Control Set-up
The
hydro
CHEM
control function must be set up correctly before attempting to use the
hydro
CHEM
for automatic control. Setting up the control function involves setting the ON and
OFF times for each pump. Conductivity and pH ON and OFF times can be set independently, to
allow for the different effects these have on the total system.
The ON time is the maximum amount of time the pump will operate continuously. For example, if
the Conductivity ON time is set to 5 minutes, the Conductivity pump will add A&B Nutrient for a
maximum of 5 minutes and then wait for the OFF time. Of course, if the Conductivity gets back
within the limit earlier, the pump will stop before the end of the 5 minutes.
The OFF time is the waiting time between ON cycles. Even if the Conductivity or pH go outside
their normal limits during the OFF time, the
hydro
CHEM
will not activate the relevant pump until
the entire OFF time has elapsed.
In the examples shown in sections 3.1 and 3.2, the ON times are both set to 5 minutes and the OFF
times are set to 10 minutes. This means that the unit will dose for a maximum of 5 minutes, then
wait for 10 minutes. These ON and OFF times cycle repetitively. At all times, the Conductivity and
pH pumps will only operate when the readings are outside the limits.
Correct use of an ON and OFF cycle will avoid overdosing problems.
3.1 Setting up the Conductivity control function
1. Select the Control menu (
→
→
F2:Control
).
2. Select
F3:Conductivity
from the menu. The following screen is now displayed…
Enter ON Time : 5 minutes, 0 = Offline
Use the
and
keys to enter the ON time for the Conductivity pump (up to 30 minutes).
Enter Zero to take the Conductivity pump off line.
Press
to save the new value, or press
to quit without saving the changes.
3. The
hydro
CHEM
then goes on to the OFF time entry…
ON Time : 5 minutes
Enter OFF Time : 10 minutes, 0 = Untimed
Use the
and
keys to enter the OFF time for the Conductivity pump (up to 30 minutes).
Enter Zero to make the Conductivity pump operate on demand whenever the reading is outside
the limit.
Press
to save the new value, or press
to quit without saving the changes.
4. The Conductivity control function is now set up and the
hydro
CHEM
returns to the Control
menu.
