Recorder output connections, Recorder – Hanna Instruments HI 9910 User Manual
Page 17
17
ALARM
ON
OFF
• The alarm ON/OFF switch is only to disable
disable
disable
disable
disable
the alarm terminal
the alarm terminal
the alarm terminal
the alarm terminal
the alarm terminal (e.g. the buzzer will
not sound). However, all other functions such as
disactivation of the dosing relay remain unvaried, i.e. the pump
ceases to dose until the alarm condition is alleviated.
• The controllers provide for automatic fail-safe
automatic fail-safe
automatic fail-safe
automatic fail-safe
automatic fail-safe security by
activating the alarm if there is a power failure, regardless of
whether the NC or NO configurations were chosen.
• The alarm is also activated if the maximum
dosage time is exceeded. The overdosage timer
can be set from 1 to 10 minutes. For HI 9911,
two timers for acid and alkaline corrections can
be independently selected.
• Once in an alarm condition, the alarm contact remains activated
until the switch is manually put in the off position or the
measurements returns to normal values.
Model
Alarm is activated when the reading varies by :
HI 9910
0 to 2.0 pH (selectable) above or below the setpoint
HI 9911
0 to 2.0 pH (selectable) lower than the ALKALINE setpoint or
higher than the ACID setpoint
HI 9920
0 to 200 mV (selectable) above or below the setpoint
ALARM DOSING TIME
MINUTES
1
10
2.5
5
7.5
RECORDER OUTPUT CONNECTIONS
• The
recorder output contacts are
isolated
isolated
isolated
isolated
isolated from the controller circuitry
to avoid interference. Select between
0 to 20 or 4 to 20 mA with the
selector (see 18 - Functional Diagram) before wiring. The output
mA value is proportional and is the pH or ORP value over the
entire range. For example, when measuring pH 7, the output
values are 10 mA or 12 mA based on whether the 0-20 or 4-20
output were respectively selected.
Output mA
selector
0/20
4/20
RECORDER
pH
0
1
2
ALARM
MTC
ATC
mA OUTPUT
TEMP. COMP.
4/20
0/20
HI 9910
pH
SECONDS
0
90
45
MTC
°C
-10
80
10
0
30
20
60
70
40
50
0
pH
2.0
0.5
1
1.5
COARSE
FINE
SLOPE
OFFSET
PROPORTIONAL SETTINGS
ALARM
ON
OFF
SET
READ
ACID
DOSING
ALK
SET POINT
ALARM DOSING TIME
MINUTES
1
10
2.5
5
7.5
SET pH
ALARM
LINE