Features
Level control relays for conductive liquids
72.01 - Adjustable sensitivity
72.11 - Fixed sensitivity
•Emptying or filling functions
•LED indicator
•
Reinforced insulation (6 kV - 1.2/50 μs) between:
- supply and contacts
- electrodes and supply
- contacts and electrodes
•35 mm rail (EN 60715) mount
•Control about a single level or between
Min./Max. limits
•72.01 available also for supply 400 V
•72.01 available also with sensitivity range
(5...450) kΩadjustable
•72.01 available also for contact loads down
to 5 V 1 mA
1 CO (SPDT) 1 CO (SPDT)
16/30 16/30
250/400 250/400
4,000 4,000
750 750
0.55 0.55
16/0.3/0.12 16/0.3/0.12
500 (10/5) 500 (10/5)
AgCdO AgCdO
24 110...125 230...240 400 24 110...125 230...240
24 — — — 24 — —
2.5/1.5 2.5/1.5
19.2...26.4 90...130 184...253 360...460 19.2...26.4 90...130 184...253
20.4...26.4 — — — 20.4...26.4 — —
100 · 103100 · 103
44
0.2 0.2
0.5 - 7 (selectable) 1
5…150 (adjustable) 150 (fixed)
66
–20…+60 –20…+60
IP20 IP20
•Sensitivity range (5...150) kΩadjustable
•Delay time (0.5s or 7s) switch selectable
•Emptying or filling functions switch selectable
•Sensitivity fixed 150 kΩ
•Delay time fixed: 1s
•Emptying or filling functions link selectable
Contact specification
Contact configuration
Rated current/Maximum peak current A
Rated voltage/Maximum switching voltage V AC
Rated load AC1 VA
Rated load AC15 (230 V AC) VA
Single phase motor rating (230 V AC) kW
Breaking capacity DC1: 30/110/220 V A
Minimum switching load mW (V/mA)
Standard contact material
Supply specification
Nominal voltage (UN) V AC (50/60 Hz)
V DC
Rated power AC/DC VA (50 Hz)/W
Operating range V AC (50/60 Hz)
V DC
Technical data
Electrical life at rated load AC1 cycles
Electrode voltage V AC
Electrode current mA
Run-on time s
Max sensitivity range kΩ
Insulation between supply/contacts/electrode (1.2/50 μs)
kV
Ambient temperature °C
Protection category
Approvals (according to type)
U = 24 V DC
24 V AC 50/60 Hz
(110...125)V AC 50/60 Hz
(230...240)V AC 50/60 Hz
U = 24 V DC
24 V AC 50/60 Hz
(110...125)V AC 50/60 Hz
(230...240)V AC 50/60 Hz
FL = Filing – 7s delay
FS = Filling – 0.5s delay
ES = Emptying – 0.5s delay
EL = Emptying – 7s delay
F = Filling
E = Emptying
1
FOR UL RATINGS SEE:
“General technical information” page V
For outline drawing see page 8
72.01 72.11
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72.01/11
Screw terminal
72 Series - Monitoring relays 72
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2
Features
Priority change relay
Special relay for alternating loads,
for applications with pumps, compressors,
air conditioning or refrigeration units
•2 independent NO output, 12 A
•4 functions
•2 independent control signals, insulated from
supply
•110...240 V and 24 V AC/DC supply versions
•Modular housing, 35 mm wide
•35 mm rail (EN 60715) mount
•Cd-free contact material
2 NO (2 DPST-NO)
12 / 20
250 / 400
3,000
1,000
0.55
12 / 0.3 / 0.12
300 (5 / 5)
AgNi
24 110 … 240
0.12 0.18
1.1 / 1.7 1.5 / 3.9
16.8…28.8 90…264
16.8…32 90…264
100 x 103
0.2...20
≤ 0.7
50
6
1,000
–20…+50
IP20
•Multi-function (MI, ME, M2, M1)
Contact specification
Contact configuration
Rated current / Max. peak current A
Rated voltage / Max. switching voltage V AC
Rated load AC1 VA
Rated load AC15 VA
Single phase motor rating (230 V AC) kW
Breaking capacity DC1: 30/110/220 V A
Minimum switching load mW (V/mA)
Standard contact material
Supply specification
Nominal voltage (UN) V AC (50/60 Hz) / DC
Rated power in stand-by W
with 2 active relays W/VA(50 Hz)
Operating range V AC (50/60 Hz)
V DC
Technical data
Electrical life at rated load AC1 cycles
Output delay time (T on function diagrams) s
Power-on activation time s
Minimum impulse duration ms
Insulation between supply and contacts (1.2/50 μs) kV
Dielectric strength between open contacts V AC
Ambient temperature °C
Protection category
Approvals (according to type)
72.42
72.42
Screw terminal
For outline drawing see page 8
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SERIE S72 Series - Monitoring relays
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Example: 72 series level control relay, adjustable sensitivity range, (230…240)V AC supply voltage.
Series
Type
0 = Level control relay,
sensitivity range adjustable (5...150)kΩ
1 = Level control relay, sensitivity fixed 150 kΩ
4 = Priority change relay
No. of poles
1 = 1 CO (SPDT)
2 = 2 NO (DPST-NO)
Contact material
0 = Standard AgCdO
for 72.01/72.11,
AgNi for 72.42
5 = AgNi + Au**
Supply voltage
024 = 24 V
125 = (110…125)V AC
230 = (110 … 240) V
240 = (230…240)V AC
400 = 400 V AC (72.01 only)
Supply version
0 = DC / AC (50/60 Hz)
8 = AC (50/60 Hz)
9 = DC
All versions
72.01.8.024.0000
72.01.8.024.0002*
72.01.8.125.0000
72.01.8.240.0000
72.01.8.240.0002*
72.01.8.240.5002**
72.01.8.400.0000
72.01.9.024.0000
72.11.8.024.0000
72.11.8.125.0000
72.11.8.240.0000
72.11.9.024.0000
72.42.0.230.0000
72.42.0.024.0000
* For liquids conductivity up to 2 μSiemens
or a Resistance of 450 kΩ
** For applications with output contact loading down to 5 V
1 mA
0 1 0 08 0 0
Ordering information
... .
24072
3
Option
0 = Max. 150 kΩ
2 = Sensitivity range
adjustable (5...450) kΩ
types 72.01.8.024.0002*
72.01.8.240.0002*
72.01.8.240.5002**
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Technical data
4
* There is no electrical isolation between electrodes and supply voltage for the 24 V DC types (72.x1.9.024.0000). Therefore, for SELV
applications it would be necessary to use a SELV (non-grounded) power supply. In the case of a PELV (grounded) power supply take care to
protect the level control relay against harmful circulating currents by ensuring that no electrodes are grounded.
However, there is no such problem for the 24 V AC types (72.x1.8.024.0000) which, by virtue of an internal isolating transformer, assure
reinforced isolation between electrodes and supply.
Insulation 72.01/72.11 72.42
Insulation Dielectric strength Impulse (1.2/50 μs)
between supply and contacts 4,000 V AC 6 kV 6 kV
between supply and control (for 110…240 V version only) 2,500 V AC — 4 kV
between electrodes, Z1-Z2 and supply* 4,000 V AC 6 kV —
between contacts and electrodes 4,000 V AC 6 kV —
between open contacts 1,000 V AC 1.5 kV 1.5 kV
EMC specifications
Type of test Reference standard 72.01/72.11 72.42
Electrostatic discharge contact discharge EN 61000-4-2 4 kV 4 kV
air discharge EN 61000-4-2 8 kV 8 kV
Radio-frequency electromagnetic field (80...1,000 MHz) EN 61000-4-3 10 V/m 10 V/m
(1…2.8 GHz) EN 61000-4-3 — 5 V/m
Fast transients on supply terminals EN 61000-4-4 4 kV 4 kV
(burst 5/50 ns, 5 and 100 kHz) on control terminals EN 61000-4-4 — 4 kV
Voltage pulses on supply terminals common mode EN 61000-4-5 4 kV 4 kV
(surge 1.2/50 μs) differential mode EN 61000-4-5 4 kV 4 kV
Radiofrequency common mode on supply terminals EN 61000-4-6 10 V 10 V (0.15...230 MHz)
voltage (0.15…280 MHz) on control terminals EN 61000-4-6 — 10 V
Voltage dips 70 % UNEN 61000-4-11 — 25 cycles
Short interruptions EN 61000-4-11 — 1 cycles
Radiofrequency conducted emissions (0.15…30 MHz) CISPR 11 class B class B
Radiated emissions (30…1,000 MHz) CISPR 11 class B class B
Terminals
Screw torque Nm 0.8
Wire strip length mm 9
Max. wire size solid cable stranded cable
mm2 1x6 / 2x4 1x4 / 2x2.5
AWG 1x10 / 2x12 1x12 / 2x14
Other data
Current absorption on Z1 and Z2 (type 72.11) mA < 1
Current absorption on control signal (B1-B3 and B2-B3) 5 mA, 5 V
Power lost to the environment 72.01/72.11 72.42
without contact current W 1.5 0.9 (1 relay ON)
with rated current W 3.2 3.0 (2 relays ON)
Max cable length between electrode and relay (types 72.01/72.11) m 200 (max. capacitance of 100 nF/km)
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SERIE S72 Series - Monitoring relays
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Functions for 72.01 and 72.11
Contacts
NO output
contact
Supply
voltage
LED
OFF
ON
ON
ON
U= Supply voltage
B1 = Max level
electrode
B2 = Min level
electrode
B3 = Common
= Contact 11-14
Z1-Z2 = Link to select
emptying
(Type 72.11)
Open
Open
Open
(Timing in Progress)
Closed
11 - 14
11 - 14
11 - 14
11 - 12
11 - 12
11 - 12
11 - 12
11 - 14
Open Closed
Function and Run-on time
Type 72.01 Type 72.11
FL = Level control by Filling, Long (7sec) run-on delay. F = Level control by Filling, Z1–Z2 open. Run-on time fixed at 1sec.
FS = Level control by Filling, Short (0.5sec) run-on delay. E = Level control by Emptying, Z1–Z2 linked. Run-on time fixed at 1sec.
ES = Level control by Emptying, Short (0.5sec) run-on delay.
EL = Level control by Emptying, Long (7sec) run-on delay.
Filling functions
Wiring diagram Examples with 3 electrodes
Wiring diagram Examples with 2 electrodes
Type 72.01 Filling Control – between Min.
and Max. levels.
Under normal operation the liquid
level can be expected to cycle
between the Minimum and the
Maximum electrodes, B2 and B1
(plus a degree of over and
under-shoot).
Switch On:
• On “power-up”, if the liquid is
below B1 the output relay will
operate after time T has expired.
• On the liquid level falling below
B2, the output relay will operate
after time T has expired.
Switch Off:
• On the liquid level reaching
electrode B1, the output relay will
de-energise after time T has
expired.
• On “power-off”, the output relay
will immediately de-energise.
Type 72.01 Filling Control – about a single
level, B1.
Under normal operation the liquid
evel 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
below B1 the output relay will
operate after time T has expired.
• On the liquid level falling below
B1, the output relay will operate
after time T has expired.
Switch Off:
• On the liquid level reaching
electrode B1, the output relay will
de-energise after time T has expired.
• On “power-off”, the output relay
will immediately de-energise.
Type 72.11
Type 72.11
U = 24 V DC
24 V AC 50/60 Hz
(110...125)V AC 50/60 Hz
(230...240)V AC 50/60 Hz
U = 24 V DC
24 V AC 50/60 Hz
(110...125)V AC 50/60 Hz
(230...240)V AC 50/60 Hz
F = Filling
F = Filling
Level
Level
5
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Emptying functions
Wiring diagram Examples with 3 electrodes
Type 72.01 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.
Type 72.01 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
Type 72.11
Type 72.11
U = 24 V DC
24 V AC 50/60 Hz
(110...125)V AC 50/60 Hz
(230...240)V AC 50/60 Hz
U = 24 V DC
24 V AC 50/60 Hz
(110...125)V AC 50/60 Hz
(230...240)V AC 50/60 Hz
E = Emptying
E = Emptying
Level
Level
6
Wiring diagram Examples with 2 electrodes
Applications for 72.01 and 72.11
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
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.
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SERIE S72 Series - Monitoring relays
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7
Functions for 72.42
LED
Device in stand-by, output not activated
Output not activated, timing in progress
Output not activated (only functions M1/M2)
Output activated
A1-A2 = Supply voltage
S1 (B1-B2) = Control signal 1
S2 (B3-B2) = Control signal 2
= Contact 1 (11-14) and
Contact 2 (21-24)
LED 1 = Output 1
LED 2 = Output 2
(MI) Outputs alternate on successive applications of
supply voltage
• Application of the supply voltage to A1-A2 forces
just one output contact to close, but the contact that
closes will alternate between 11-14 and 21-24 on
each successive application of the supply – ensuring
even wear across both motors.
• The other output contact can be forced closed by the
closure of either S1 or S2 - but to limit high current
surges the other motor cannot start within T seconds of
the first motor.
(ME) Outputs alternate according to control signal
• The supply voltage is permanently applied to A1-A2.
When closed, S1 forces just one output contact to
close. The contact that closes will alternate between
11-14 and 21-24 on each successive S1 closure -
ensuring even wear across both motors.
• If closed, S2 forces both output contacts to close
(irrespective of S1). However, to limit high current
surges, both motors cannot start within T seconds of
each other.
(M2) Output 2 (21-24) only
• Supply permanently applied to A1-A2.
• Closure of either S1 or S2 will close output contact
2 (21-24). Use when load 1 (11-14) is out of
service.
(M1) Output 1 (11-14) only
• Supply permanently applied to A1-A2.
• Closure of either S1 or S2 will close output contact
1 (11-14). Use when load 2 (21-24) is out of
service.
Wiring diagram
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MI function example
This shows the 72.42 Priority change relay working in conjunction
with a single 72.01 level controller. Under normal conditions the
liquid level is expected to remain within the range shown as Min
to Max. In this case the function of the 72.42 will be to alternate
the duty between both pumps, to even wear across both pumps.
There is no provision to run both pumps simultaneously.
Outline drawings
72.42
Screw terminal
72.01/11
Screw terminal
ME function example
This shows the 72.42 Priority change relay working in conjunction
with two 72.01 level controllers. Under normal conditions the
liquid level is expected to remain within the range shown as Min
to Max. In this case the function of the 72.42 will be to alternate
the duty between both pumps, to even wear across both pumps.
Should the liquid level rise above the Alarm level then the function
of the 72.42 will call for the simultaneous operation of both
pumps, by virtue of the signal to terminal B3 from the Alarm/Low
level controller.
Note: due to the low level of 72.42 control signals, it is suggested
to use level controller 72.01.8.240.5002 because of its superior
low load switching capability.
8
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9
Accessories for 72.01 and 72.11
Suspended electrode for conductive liquids, complete with cable. Suitable for level monitoring in wells and reservoirs not
under pressure.
Order appropriate number of electrodes - additional to the relay.
•Electrode compatible with food processing applications (according to European Directive 2002/72 and cod. FDA
title 21 part 177):
Cable length: 6 m (1.5 mm2) 072.01.06
Cable length: 15 m (1.5 mm2) 072.01.15
• Electrode for swimming pools with high levels of chlorine, or in salt-water pools with high levels of salinity:
Cable length: 6 m (1.5 mm2) 072.02.06
Technical data
Max. liquid temperature °C +100
Electrode material stainless steel (AISI 316L)
072.01.06
072.02.06
Suspended electrode
Order appropriate number of electrodes additional to the relay. 072.31
Technical data
Max liquid temperature °C + 80
Cable grip mm Ø ≤3...6
Electrode material stainless steel (AISI 316L)
Max screw torque Nm 0.7
Max. wire size mm21 x 2.5
AWG 1 x 14
Wire strip length mm 9
072.31
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10
Electrode holder with two pole connector, one connected directly to the electrode and the second
connected to the grounded installation thread. Suitable for metal tank with G3/8” linkage.
Electrode not incuded. Order appropriate number of electrodes holders - additional to the relay. 072.51
Technical data
Max liquid temperature °C + 100
Max tank pressure bar 12
Cable grip mm Ø ≤6
Electrode material stainless steel (AISI 304)
072.51
Floor water sensor, designed for the detection and reporting of the presence of floor surface water. 072.11
Technical data
Electrode material stainless steel (AISI 301)
Wire capability of terminals
Max screw torque Nm 0.8
Max. wire size solid cable stranded cable
mm21 x 6 / 2 x 6 1 x 6 / 2 x 4
AWG 1 x 10 / 2 x 10 1 x 10 / 2 x 12
Wire strip length mm 9
Other data
Distance between electrodes and floor mm 1
Floor fixing screw diameter Maximum M5
Maximum cable diameter mm 10
Maximum length of cable connecting sensor to relay m 200 (with capacitance of 100 nF/km)
Max. liquid temperature °C +100
072.11
Floor surface water sensor for connection to electrode terminals
(B1 and B3) of 72.01 or 72.11 level control relay, set in
Emptying function (ES or E respectively).
For ice bank control in refrigeration systems it is suggested to use
the high sensitivity (5...450kOhm) types - 72.01.8.024.0002 or
72.01.8.230.0002.
Function
Z1, Z2 only for types 72.11
Accessories for 72.01 and 72.11
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11
072.500
Accessories for 72.01 and 72.11
072.501
Illustration of interconnection of electrodes.
Electrode and electrode connector, multiple electrodes may be interconneced to provide required length
Technical data
Electrode - 500 mm long, M4 thread, stainless steel (AISI 303) 072.500
Inter-electrode connector - M4 thread, stainless steel (AISI 303) 072.501
072.503
Electrode separator 072.503
Electrode holder with three poles. Electrode not incuded.
Order appropriate number of electrodes holders - additional to the relay. 072.53
Technical data
Max liquid temperature °C + 130
Electrode material stainless steel (AISI 303)
072.53
Adaptor for panel mounting, plastic, 35 mm wide 011.01
011.01
Identification tag, plastic, 1 tag, 17 x 25.5 mm (for 72.42 only) 019.01
Sheet of marker tags, plastic, 72 tags, 6 x 12 mm (for 72.42 only) 060.72
060.72
019.01
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Applications
The main application for these relays is for the sensing and control of the
level of conductive liquids.
Selectable options allow for this control to be achieved either through a
filling operation or through an emptying operation, and in either case
“positive logic” is used.
Level control can be achieved around a single level – using 2 electrodes,
or between Minimum and Maximum levels – using 3 electrodes.
Additionally, the 72.01, with its adjustable sensitivity setting, can be
ideal for monitoring the conductivity of liquids.
Positive safety logic
These relays work according to the principle that it is the closure of a
normally open output contact that will be used to control the pump, both
in filling and emptying applications. Consequently, in the event of a
failure of the supply local to the relay, the filling or emptying will cease.
This is generally considered to be the safest option.
Overrunning of tank on filling
Care must be exercised to ensure that the tank cannot overrun. Factors
that have to be considered are the pump performance, the rate of
discharge from the tank, the position of the single level electrode (or
maximum electrode), and the run-on time delay. Keeping the time delay
to a minimum will minimise the possibility of tank overrun, but will increase
the installed switching rate.
Prevent dry running of pump on emptying
Care must be exercised to ensure that the pump cannot run dry. Similar
considerations must be given as outlined above. In particular, keeping the
run-on time delay to a minimum will minimise the risk, but again, it will
increase the installed switching rate.
Run-on time
In commercial and light industrial applications the use of a short Run-on
time delay is more appropriate, due to the relatively small size of tanks
and the consequential need to react quickly to the change in level.
Larger scale industrial applications involving larger tanks and powerful
pumps must avoid a frequent switching cycle, and the use of the 72.01
set for the longer Run-on time of 7 seconds is suggested.
Note that the short run-on time will always achieve closer control to the
desired level(s), but at the cost of more frequent switching.
Electrical life of the output contact
The electrical life of the output contact will be enhanced where a larger
distance between the Max. and Min. electrodes (3-electrode control)
can be realised. A smaller distance, or level control to a single level
(2-electrode control), will result in more frequent switching and therefore
a shorter electrical life for the contacts. Similarly, the long run-on time will
enhance, and the short time will reduce, electrical life.
Pump control
Small single-phase pumps within the kW (0.55 kW - 230 V AC) rating
stated may be driven directly by the level relay output contact. However,
where very frequent switching is envisaged, it is better to “slave” a higher
power relay or contactor to drive the pump motor. Large pumps (single-
phase and three-phase) will of course require an interposing contactor.
Water leakage and condensation in oil lubrication systems
To detect condensed water vapour or water leakage within lubricating
systems, monitor by sensors connected to B1 - B3 (Function E or ES, Z1
- Z2 linked). Condensed water vapour has low conductivity, therefore
choose monitoring relay type 72.01.8.240.0002 with sensitivity range
of (5...450) kOhm and sensor type 072.11.
Floor flooding control
To detect floor water due to spills or flooding, monitor using sensors
connected to B1 - B3 (Function E or ES, Z1 - Z2 linked).
Choose monitoring relay type 72.01.8.240.0000 or 72.11.8.240.0000,
together with floor water sensor type 072.11.
Application notes for 72.01 and 72.11
Electrodes and cable lengths
Normally 2 electrodes or 3 electrodes will be required for control about
a single level, or control between Min. and Max. levels, respectively.
However, if the tank is made of conductive material it is possible to use
this as the common electrode, B3, if electrical connection can be made
to it.
The maximum permitted length of cable between the electrode and the
relays is 200m, for a cable not exceeding 100nF/km.
A maximum of 2 relays and associated electrodes can be employed in
the same tank – if two different levels need monitoring.
Note: It is permitted to make direct electrical connection between
terminals B1-B3, and B2-B3, (without using electrodes/liquid), but in this
case it is not possible to set up the sensitivity.
Electrode choice
The choice of electrodes may depend on the liquid being monitored.
Standard electrodes 072.01.06 and 072.51 are suitable for many
applications but some liquids may be corrosive for example, and may
therefore require custom made electrodes - but these can usually be used
with the 72.01 and 72.11 relays.
On site commissioning
To confirm the suitability of the relay sensitivity to the resistance between
electrodes it is suggested that the following checks are made.
For convenience it is suggested that the fill function and the shortest
run-on time are selected.
Commissioning
Follow these setting-up instructions to achieve correct operation:
72.01
Select the function “FS” (Filling and Short delay of 0.5 s), and set the
sensitivity control to 5 kΩ. Ensure that all electrodes are immersed in the
liquid - expect the output relay to be ON. Then, slowly rotate the
sensitivity control in the 150 kΩdirection until the level relay switches OFF
(internal output relay will switch OFF and red LED will switch
slowly flash).
(If the level relay does not switch OFF then, either the electrodes are not
immersed, or the liquid has too high impedance or the distance between
electrodes is too long).
Finally, select the filling or emptying function as required, run in real time
and confirm that the level relay works as required.
72.11
Select the Filling function “F”, (Z1 – Z2 open). Ensure that all electrodes
are immersed in the liquid, but leave electrode B3 disconnected – output
relay should be ON. Connect electrode B3, and the level relay should
switch OFF
(internal output relay will switch OFF and red LED will switch slowly
flash).
(If the level relay does not switch OFF then, either the electrodes are not
immersed, or the liquid has too high impedance or the distance between
electrodes is too long.)
Finally, select the filling or emptying function as required, run in real time
and confirm that the level relay works as required.
III-2014, www.findernet.com
72
SERIE S72 Series - Monitoring relays
E
