Hanna Instruments HI 8050 - Manual (Page 58)

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ALARMS DESCRIPTION ALARMS DESCRIPTION ALARMS DESCRIPTION ALARMS DESCRIPTION ALARMS DESCRIPTION
There are 10 kinds of possible software alarms that may occur during the
operation the Fertigation Controller.
1. pH Out of range
This alarm is triggered when the value of the pH sensor is outside of the
allowable dead band determined by the specified pH Reference value
together with the pH min and pH max offset limits for a period of time
specified in time-out. These parameters can be set using panel S36
S36 S36 S36 S36 (PH
CONTROL).
2. EC Out of range
This alarm is triggered when the value of the EC sensor is outside of the
allowable dead band determined by the specified EC Reference value
together with the EC min and EC max offset limits for a period of time
specified in time-out. These parameters can be set using panel S38 (EC
CONTROL).
3. Dirty filter: n
This alarm indicates that the “n” designated filter requires cleaning. The
customizable alarm behavior of the Fertigation Controller allows
automatic execution of the corresponding filter cleaning program or only
the alarm with continuation of normal function with no execution of a
filter-cleaning program. These parameters can be set using panel S45
(FILTERS CTRL), “Clean on alarm” option.
NOTE: This option, when set for filter # 1 or filter # 2, applies to BOTH
filter-cleaning programs.
4. Low level fert: n
This alarm is triggered if the fertilizer level of the “n” designated tank has
reached a minimum value. Once this alarm is triggered, the assigned
the temperature sensor in the water and ice mixture along with the refer-
ence thermometer. Allow the temperature readings to stabilise for both
controller and reference thermometer. In the calibration panel select chanel
4 (temperature sensor) and press the SET key. Introduce the temperature in
the reference field according to the reference thermometer.Press the EN-
TER keyto confirm. For this step the reference value should be 0. For the
second stage replace the ice-water mixture with hot water (about 50°C).
Follow the same procedure as in step one. This procedure might take
some time until the temperature and sensor readings stabilise. Please keep
water temperature constantduring the calibration procedure.