Hanna Instruments HI 8050 - Manual (Page 59)

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valve will close and that fertilizer tank will be excluded from use during
fertilization control of the irrigation process.
5. Low level acid
This alarm is triggered if the level of the acid (or alkaline) tank has
reached a minimum value. Once this alarm is triggered, the assigned
valve will close and that tank will be excluded from use during pH
control of the irrigation process.
6. No water supply
This alarm is triggered due to an incoming water supply failure event.
The water supply problem is considered only if the Water Incoming
Presence sensor signals that is no water on a water source that is used
by the current irrigation program. The Fertigation Controller is automati-
cally switched to BLOCK state and all irrigation programs are SUS-
PENDED until this event clears. Once the event is cleared the Fertiga-
tion Controller automatically resumes normal operation in the previous
state without any external intervention.
7. IRRIGATION COUNTER FAILURE
This alarm is triggered if the main pump is working but no flow is
detected trough the main counter. In this situation the controller enters
the STOP mode! The maximum time between 2 transition of the main
pump is set in panel S56
S56 S56 S56 S56 (SET FLOW PARAMS): Max. time. If for a
duration of Max. time. no transition is detected then the controller
generates the alarm and enters in STOP mode.
8. OVERDOSE ALARM.
This alarm is triggered when the dosed value is greater than the needed
value for the specific amount of water. Of course the amount of fertilizer
is set for each program and each fertilizer tank, but there is only one
global value that describes the overdose limit (percentage) referred here
as the overdose threshold. If the dosed value is greater than the needed
value plus a fraction from the needed value defined by the overdose
threshold than the overdose alarm is triggered:
When the alarm is triggered the user has the option to put the controller
into stop state (see panel 53 (STOP ON VOL ALRM)).
When entering the stop state the controller will decrease the dosed value
to the needed value of fertilizer so the program can be restored manu-
ally, this is up to the user, and the user must be aware of the effects of
this situation.
9. UNDERDOSE ALARM:
This alarm is similar to the previous one except that it describes the
situation when the amount of a specific fertilizer is too low in the