Hanna Instruments HI 9912, Инструкция по эксплуатации

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15
Make sure that the electrode (and any ground probe) is properly
installed and calibrated (see the preceding pages).
FOR pH
Simply turn the pH ACID FEED dial (see 3 - Func-
tional Diagram) and choose the desired value between
6 and 8 pH.
DOSING DIRECTION
The dosing terminals are activated when the pH value exceeds the
setpoint. HI 9912 will then dose acidic solutions until the user-selected
setpoint is reached.
ADJUSTEMENT OF SETPOINT(S) ADJUSTEMENT OF SETPOINT(S)
ADJUSTEMENT OF SETPOINT(S) ADJUSTEMENT OF SETPOINT(S)
ADJUSTEMENT OF SETPOINT(S)
FOR ORP
Simply turn the ORP OXID FEED dial (see 11 -
Functional Diagram) and choose the desired value
between 500 and 900 mV
DOSING DIRECTION
The dosing terminals are activated when the ORP falls below the
setpoint. HI 9912 will dose oxidants until the user-selected setpoint is
reached.
pH
ALARM
8
SET
FEED
6
7
ACID
500
900
SET
FEED
mV ALARM
OXID
700
0
SECONDS pH
2.0
0 90
PROPORTIONAL SETTINGS
0.5 1.5
0
SECONDS mV
200 0 90
PROPORTIONAL SETTINGS
50 150
PROPORTIONAL CONTROL PROPORTIONAL CONTROL
PROPORTIONAL CONTROL PROPORTIONAL CONTROL PROPORTIONAL CONTROL
In order to optimize the controlling process and reduce the amount of
chemicals used, it is recommended to use a proportional dosage
appropriate for the system.
HI 9912 allows for a proportional
band of 0 to 2.0 pH and 0 to
200 mV (delta) as well as two
independent time cycles from 0 to
90 seconds. The proportional dos-
age is obtained by personalizing a
current pulse whose height equals
the pH or ORP proportional delta
and the length corresponds to the
selected time cycle.
The controller will enter proportional dosage at setpoint
proportional dosage at setpoint
proportional dosage at setpoint proportional dosage at setpoint proportional dosage at setpoint
minus minus
minus minus minus (in case of ORP) or plus
or plus
or plus or plus or plus (for pH) the preselected delta
the preselected delta
the preselected delta the preselected delta the preselected delta.
It will then keep the dosing relays activated for a period proportional