Data Sheet

E
Emptying functions
Wiring diagram Examples with 3 electrodes
Type 72.01
U = 24VDC
24VAC 50/60Hz
(110…125)VAC 50/60Hz
(230…240)VAC 50/60Hz
Type 72.11
E = Emptying
Level
Emptying Control - between Max.
and Min. levels.
Under normal operation the liquid
level can be expected to cycle
between the Maximum and the
Minimum electrodes, B1 and B2 (plus
a degree of over and under-shoot).
Switch On:
• On “power-up”, if the liquid level
is above B2 the output relay will
operate after time T has expired.
• On the liquid level rising to B1, the
output relay will operate after time T
has expired.
Switch Off:
• On the liquid level falling below
electrode B2, the output relay will
de-energise after time T has expired.
• On “power-off”, the output relay
will immediately de-energise.
Wiring diagram Examples with 2 electrodes
Type 72.01
U = 24VDC
24VAC 50/60Hz
(110…125)VAC 50/60Hz
(230…240)VAC 50/60Hz
Type 72.11
E = Emptying
Level
Emptying Control about a single
level, B1.
Under normal operation the liquid
level can be expected to cycle about
the level set by electrode B1 with a
degree of over and under-shoot.
Switch On:
• On “power-up”, if the liquid is
above B1 the output relay will
operate after time T has expired.
• On the liquid level rising to B1, the
output relay will operate after time T
has expired.
Switch Off:
• On the liquid level falling below
electrode B1, the output relay will
de-energise after time T has expired.
• On “power-off”, the output relay
will immediately de-energ
Applications for 72.01 and 72.11
FILLING function:
Examples with 3 electrodes and with a contactor
connected to the contact.
EMPTYING function:
Examples with 3 electrodes and with a motor
pump connected directly to the contact.
The 72 series level control relays work by
measuring the resistance through the liquid,
between the common (B3) electrode and Min. and
Max. electrodes (B2 and B1). If the tank is metalic,
then this can be substituted as the B3 electrode.
Take care to ensure that the liquid has a suitable
resistivity – see below:
SUITABLE LIQUIDS
– City water
– Well water
– Rainwater
– Sea water
– Liquids with low-percentage alcohol
– Wine
– Milk, Beer, Coffee
– Sewage
– Liquids fertilizer
UN-SUITABLE LIQUIDS
– Demineralised water
– Fuels
– Oil
– Liquids with high-percentage alcohol
– Liquid gas
– Paraffins
– Ethylene glycol
– Paint
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IV-2018，www.findernet.com
72 SERIES
Monitoring relays
72
SERIES