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SC100/200 Series Function Block Application Manual EM-6460-C
4.3.13 ON/OFF CONTROL
High/low alarm block is used to achieve ON/OFF control or interlocking.
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LOOP CONFIGURATION EXAMPLES
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BLOCK DIAGRAM FOR THE EXAMPLE (1)
steam
temp
TC
level
PV
PV
PV
MV
LS
M
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Example (1): Temperature control
water
level
LC
LIC
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Example (3): Maintaining the minimum liquid level in a tank
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Example (2): Interlocking to prevent idle
running of an agitator
feed
evaporator
Water is supplied to maintain the minimum liquid
level when it reaches the low limit after the feed
has been stopped.
ON/OFF
(open/close)
ON/OFF
ON/OFF
(open/close)
pump
X1
PV
DO
PVA
High/Low Alarm
Sequence
G30
SEQ
G81
high alarm output
temp