Download PH400G Intelligent Outdoor pHConverter

6. Operation
Note 3: Proportional frequency pulse contact output
Proportional frequency pulse contact output is an output method which performs
ON/OFF action by controlling relay contact output fixed pulse (0.3 sec.)
occurrence time (t), or occurrence frequency (1/t), in proportion to the pH value
change within the set control range.
This proportional frequency pulse contact output function is effective only when
the lower limit 1 alarm (LOW) or the upper limit alarm (HIGH) is selected.
An example is shown in Figure 6.5. As (a) in the figure shows, while the pHvalue is below the alarm point, the relay contact is always OFF (open). As the
pH value increases to reach or exceed the value which is obtained by adding
100% of the set control range to the alarm point, a fixed pulse occurs with the
cycle(t) in proportion to the maximum frequency of the set pulse(1/t) as (b)
shows. The relay contact is ON (closed) for 0.3 sec during the fixed pulse
occurrence. The fixed pulse cycle within the set control range is given below as
shown in Figure 6.5.
t3(100/x) (0< x %100%)
Here pH value is expressed in x% or control range (0 to 100%) starting from
the alarm point. (Refer to Figure 6.5)
t
Control output [%]
t3
(g)
100
X
100
X
0.3s (Fixed)
(b)
50
2t
No pulse
(a)
0
Control range
Alarm point
Settable parameters
? pH alarm point
? Control range
? Pulse maximum frequency
pH
Time
F6.5E.eps
Figure 6.5 An Example of Proportional Frequency Pulse Contact Output
(in the Case of Upper Limit Alarm)
Note 4: When using relay contact output (S1, S2, S3, FAIL), be sure to use them within
the contact rating allowance.
Note 5: If the pH converter is in hold status ( HOLD lamp lit.) or in abnormality
occurrence ( FAIL lamp lit) when the upper alarm( HIGH) or lower alarm
(LOW) (in the case of S3, includes high-high or low-low alarm) is selected as
the relay contact output (S1, S2, S3) function, these contact outputs will be
temporarily ineffective, whichever contact output method is selected.
(o) Code 15:
IM 12B7C1-02E
Contact output S2 function selection (*S2)
d Contact output function selection
Select 0 when contact output S2 is turned to OFF, select 1 when lower alarm (LOW) is
required, select 2 when upper alarm (HIGH) is required and select 3 when hold (HOLD)
is required. Set 0 (OFF) without fail when contact output S2 is not used. 0 (OFF) is set
at the time of shipment.
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