Follow instruction manual
The instruction manual is part of the product and an important element within the safety
concept.
• Read and follow instruction manual.
• Always keep instruction manual available for the product.
• Pass on instruction manual to all subsequent users of the product.
1. Intended use
The product is applicable for liquids with specific conductivity over 10 µS/cm. The
switching unit can sense the resistance between probes. Conductivity measurement is
suitable only for detecting the presence of liquid at a given level of the tank. This level
is represented by the length of the probe. The conductive switch is suitable for fìlling or
emptying control with 2 to 4 relay outputs working simultaneously or for level detection
of 2-4 independent levels (in 1 or 2 tanks) with 2 independent relay outputs.
2. Safety and responsibility
In order to provide safety in the plant, the operator is responsible for the following
measures:
• Products may only be used for its intended purpose, see intended use
• Never use a damaged or defective product.
Immediately sort out damaged product.
• Make sure that the piping system has been installed professionally and serviced
regularly.
• Products and equipment shall only be installed by persons who have the required
training, knowledge or experience.
• Regularly train personnel in all relevant questions regarding locally applicable
regulations, safety at work, environmental protection especially for pressurised pipes.
The personnel is responsible for the following measures:
• Know, understand and follow the instruction manual and the advices therein.
3. Function
The level switch consists of 1 or 2 switching unit and the KLN-2 type probes. Probes are
to be connected to the 2281 type probe socket head that can be screwed into the tank.
lf the material of the tank or its internal insulation is not conductive then a reference
probe should be used in addition to the one, two, three or four probe(s), if the material of
the tank is conductive, the tank can be used as a reference probe.
4. Technical Data
4.1 Technical Data of the switching unit
Probe Voltage
5 V AC
Probe current
< 1 mA AC
Sensitivity
Adjustable: 5 kΩ ... 100 kΩ
Max. cable capacity
4 nF
Response
max. 400 ms
Setting accuracy (mech.) ± 5 %
Delay
Adjustable: 0.5 ... 10 s
Relay output
2x SPDT
Switching voltage
250 V AC1, 24 V DC
Switching current
16A AC1
Switching power
4000 vA AC1. 384 W DC
Electrical strength
4 kV
Mechanical life-span
3 x10
7
switches
Electrical life-span
0,7x10
5
switches
Power supply Un
24 V AC/DC
Voltage range allowed
nominal voltage -15 %...+100 %
Power consumption
max. 2.5 VA/ W
Ambient temperature
-20°C ... +55°C
Electrical connection
max. 2.5 mm
2
/ with insulation 1.5 mm
2
Electrical protection
Class III
Ingress protection
IP 20
Mechanical connection
DIN EN 60715 rail
Mass
240 g
5. Dimensions
Switching unit: 2281-2-Relay
52
45
67,5
90
65
19
21
56,5
Separatur KLP-201
Probe KN-2xx
38
38
Ø
6
6. Installation
• Mount switching unit on DIN EN 60715 rail.
• Cut the KLN-2 type probes to the length required for level detection on site.
• Screw probes into the sockets.
• Tighten the probe with an M6 nut.
• Use separators at every 0.5 m for multiple probe devices to keep the probes apart.
7. Electrical Connection
lf the wall of the tank is conductive no reference probe is needed, ln this case terminal C
is to be connected to the tank. On multiple probe units E1 and E2 are marked with
1,,.4, the reference probe is marked with C. Admissible length of cable between signal
processor and probes depends on cable capacity and conductivity. Make sure E1 in
upper level, E2 buttom level.
A1 A2
E1
E2
C
S
16 15
25
28
18
26
U
n
A1, A2 - power supply
C - reference probe
E1 - upper level probe
E2 - bottom level probe
S - shielding
15, 16, 18 - 1. relay output
25, 26, 28 - 2. relay output
E1 max. probe
E2 min. probe
C reference probe
E1
E2
8. Putting into operation
8.1 Adjustment
The green LED (
U
n
) shows that the unit is on, the energized state of the relays are
indicated by the E1 respectively E2 LEDs. Operating mode, delay ON and delay OFF can
be set with the DIP switch on the front panel. tE1(s) and tE2(s) potentiometers are for
adjusting the delay time. The sensitivity setting (R potentiometer) should comply with lhe
conductivity of the fluid. Do not set sensitivity higher than required because the vapour
precipilation may lead to operation disturbance.
Selection of delay type for input E1
ta: delay OFF
tb: delay ON
Selection of delay type for input E2
ta: delay OFF
tb: delay ON
Inversion of function type for input E2
Function selection:
1x: monitoring two independent levels
2x: level control
Power supply indicator
`relay 1 energised´ indicator
`relay 2 energised´ indicator
Delay adjustment for E1
Delay adjustment for E2
Adjustment for probe sensitivity
1x
ON
tb
tb
Function 2x
Input inverse OFF
Delay type E2 ta
Delay type E1 ta
E1
E2
KRK-522
tE2(s)
tE1(s)
R(kΩ)
U
n
Georg Fischer Piping Systems Ltd CH-8201 Schaffhausen
Phone +41(0)52 631 30 26 / info.ps
@
georgfischer.com /
www.gfps.com
GFDO 6354_4 (07.14)
© Georg Fischer Rohrleitungssysteme AG
CH-8201 Schaffhausen/Schweiz, 2014
Printed in Switzerland
Instruction manual
2281 Conductive multipoint switch
with dual channel relay
GF Piping Systems