MK 9151N Level Sensing Relay

Product Information

Specifications

• Model: VARIMETER Level Sensing Relay
• Model Numbers: IL 9151, SL 9151, MK 9151N

Function Diagrams

The product has two function diagrams:

1. Common control of output relays (with bridge X1-COM)

   • X1 COM UH 0 Level MAX MIN 11-14, 21-24 X1 COM X2 (Open circuit
     operation) 11-12, 21-22 tv MAX tv MIN 11-14, 21-24 X1 (Closed COM
     circuit operation) 11-12, 21-22 tv MAX Common control of output
     relays tv MIN M6956_b

2. Separate control of output relays (without bridge X1-COM)

   • X1 COM UH 0 Level MAX MIN 21-24, 21-22 X1 COM X2 (Open circuit
     operation) 11-14, 11-12 tvMIN tv MAX tv MAX tv MIN Translation of
     the original instructions – 2 separate controllable output relays
     for MIN and MAX level – Common controlled output relays for 2-point
     hysteresis Approvals and Markings

Circuit Diagrams

The product has two circuit diagrams:

1. X1 COM X2 MIN MAX A1 A2 A1 A2 X1 X2 MIN COM MAX 12 11 14 22 21
   24 12 22 14 11 24 21 M7556_b IL 9151.12, SL 9151.12 A1 11 21 MIN X1
   COM X2 MAX A1 X1 MIN MAX 11 21 A2 X2 COM 12 14 22 24 22 24 12 14 A2
   M8502

2. MK 9151N.12 Connection Terminals Terminal designation A1, A2
   MIN, MAX, COM X1 – COM X2 – COM 11, 12, 14 21, 22, 24 Signal
   description Auxiliary voltage AC oder DC Electrode connection
   Selection operating mode via bridge Selection de-energized or
   energized via bridge Contacts Rel. 1 Contacts Rel. 2

Product Usage Instructions

1-Point Level Control

The product supports 1-point level control which is suitable for
protection against overfilling and dry running on containers with a
free inlet/outlet. To configure this setup, you will need the
reference probe COM and the MAX probe located at the desired limit
level.

The output relay will switch over after the set delay time if
the fluid level exceeds or falls below the limit level, allowing
fluid to be pumped out or added.

Separate Output Control

If separate output control is desired, where each output relay
has a separate time delay, you need to set the unit to separate
control of the outputs and connect the MIN and MAX inputs to the
same probe. Please note that the resistance of the liquid is
divided on both input circuits, so the response value must be set
to double the desired value.

Time Delay and Wave Suppression

The product has a settable time delay of 0.2 to 20 seconds for
each probe circuit. This allows you to suppress early switching
caused by waves on the liquid. Additionally, time-dependent level
control can be realized. The delay works integrating and is active
when the liquid goes over as well as under the probe level.

Foam Differentiation

The wide setting range of the product allows for an optimum
setting to differentiate between foam and liquid. The response
value must be set to a value high enough that the unit reacts when
the liquid, but not when the foam reaches the probe. During the
setting procedure, the time delay should be set to the minimum
value.

FAQ

1. 1.  **Q: What is the purpose of the VARIMETER Level Sensing  

   Relay?**

A: The VARIMETER Level Sensing Relay is designed to monitor
fluid levels in containers and control output relays based on
predefined limits.

1. 1.  **Q: Can I control both MIN and MAX levels with separate  

   relays?**

A: Yes, the product supports separate control of output relays
for MIN and MAX levels.

1. 1.  **Q: How can I differentiate between foam and  

   liquid?**

A: The product has a wide setting range that allows for
differentiation between foam and liquid. The response value must be
set accordingly.

0225266

Installation / Monitoring Technique
VARIMETER Level Sensing Relay IL 9151, SL 9151, MK 9151N

IL 9151

SL 9151

Function Diagrams

MK 9151N

Common control of output relays (with bridge X1-COM:

)

X1 COM

UH

0 Level
MAX MIN

11-14, 21-24

X1 COM X2 (Open circuit operation)

11-12,

21-22

tv MAX

tv MIN

11-14, 21-24

X1 (Closed

COM circuit

opXe2ration)11-12,

21-22

tv MAX

Common control of output relays

tv MIN

M6956_b

Separate control of output relays (without bridge X1-COM:

)

X1 COM

UH

0

Level MAX

MIN

21-24 21-22
X1 COM X2 (Open circuit operation)
11-14 11-12

tvMIN

tv MAX

tv MAX

tv MIN

Translation of the original instructions
· According to IEC/EN 60255-1 · 3 probe connections for 2-point and 1-point level control · Also for use as moisture detector · High interference resistance of the Measuring Circuit,
which is isolated from the mains · Max. wire length to the probes: 3000 m · Large setting range: 2 … 450 k
this permits differentiation between fluid and foam · Separately adjustable response and release time delay
0.2 … 20 s for MIN- and MAX-level · Programmable for:
– 2 separate controllable output relays for MIN and MAX level – Common controlled output relays for 2-point hysteresis
level control – Open circuit operation – Closed circuit operation · Measuring Circuit for probes works with internally generated AC voltage (approx. 30 Hz), electrolytic behaviour does not occur in the liquid · For auxiliary voltages of 24 … 415 V AC or 24 V DC · LEDs for operation and state of contact · 2 changeover relays with 1 changeover contact each · IL 9151 and SL 9151 with safe separation according to IEC/EN 61140, IEC/EN 60947-1 · Devices available in 3 enclosure versions: IL 9151: Depth 59 mm, with terminals at the bottom for
installation systems and industrial distribution systems according to DIN 43880 SL 9151, MK 9151N: Depth 98 mm, with terminals at the top for cabinets with mounting plate and cable duct · IL / SL 9151: 35 mm width MK 9151N: 22.5 mm width
Approvals and Markings

2. Only IL 9151, MK 9151N
   Application
   · Level monitoring and control for conductive liquids and powders, e.g. maximum and minimum filling levels, overfilling and protection against dry running
   · Monitoring and control of the mixing ratio of conductive liquids · General resistance monitoring tasks, e.g. limit temperature detection
   with PTC · Contact protection relay with time delay

21-24
21-22
X1 COM X2 (Closed circuit operation)
11-14
11-12

tvMIN

Seperate control of output relay

tv MAX

tv MAX

tv MIN

M6949_b

All technical data in this list relate to the state at the moment of edition. We reserve the right

for technical improvements and changes at any time.

1

20.06.22 en / 583A

Circuit Diagrams

X1 COM X2

MIN MAX A1 A2

A1

A2

X1

X2

MIN COM

MAX

12 11
14

22 21
24

12

22

14 11 24 21 M7556_b
IL 9151.12, SL 9151.12

A1 11 21 MIN X1 COM X2 MAX

A1 X1 MIN MAX 11

21

A2 X2 COM

12 14 22 24

22 24 12 14 A2

M8502

MK 9151N.12

Connection Terminals

Terminal designation A1, A2 MIN, MAX, COM X1 – COM X2 – COM 11, 12, 14 21, 22, 24

Signal description Auxiliary voltage AC oder DC Electrode connection Selection operating mode via bridge Selection de-energized or energized via bridge Contacts Rel. 1 Contacts Rel. 2

Notes
1-point level control 1-point level control (see Figure) is especially suitable for protection against overfilling and dry running on containers with a free inlet/outlet. In this configuration, all that is required besides the reference probe “COM” is the “MAX”, which must be located at the desired limit level. The output relay switches over after the set delay time if the fluid level exceeds or falls below the limit level, which permits fluid to be pumped out or added.
Without bridge X1 – COM only relay “MAX” (contacts 21-22-24) switch, with bridge X1 – COM both relays switch together. If for each output relay a separate time delay is necessary, the unit has to be set to separate control of the outputs and the “MIN” and “MAX” inputs are connected to the same probe. Please note that the resistance of the liquid is divided up on both input circuits. Therefore the response value must be setted to the double value.
If separate output control is selected with 1-point control for each output relay the time delay can be setted separately.
Because of the settable time delay of 0.2 to 20 sec for each probe circuit, it is possible to suppress early switching caused by waves on the liquid. Also time depending level control can be realised. The delay works integrating and is active when the liquid goes over as well as under the probe level.
The wide setting range allows easily an optimum setting so that the unit can differentiate between foam and liquid. The response value must be set to a value high enough, that the unit reacts when the liquid, but not when the foam reaches the probe (for setting procedure the time delay is set to min. value).

Indicators
IL / SL 9151 Green LED: Yellow LED: Red LED:
MK 9151N Green LED: Yellow LED “MIN”: Red LED “MAX”:

On, when auxiliary supply connected On, when relay MIN active On, when relay MAX active
On, when auxiliary supply connected On, when relay MIN active On, when relay MAX active

Notes
All commercially available probes are suitable. The reference probe for level measurement is generally located at the lowest point of the container and must always be connected to the “COM” terminal. The container itself can be used as a reference probe if it consists of conductive material.
On the level “MIN” and “MAX” the other probes are installed and connected to the corresponding inputs of IL 9151. It is also possible to connect only one probe.
2-point level control The 2-point control is selected when a liquid should be kept between “MIN” and “MAX” level. 2 operation modes can be selected:
Without bridge X1 – COM: Separate control of output relays for “MIN” and “MAX” level
With bridge X1 – COM: Common control of both output relays
When the relays are separately controlled each output relay is operated by the corresponding probe circuit. For each level the time delay can be set separately (tvMIN and tvMAX).
When the relays are controlled together, these work like a relay with 2 changeover contacts as follows:
If the liquid rises above the “MAX” level the output relays switch over after the delay time of tvMAX and start e.g. a pumpt to sink the liquid. If the level goes under the “MAX” level the output relays remain activated until the “MIN” level is reached. Now the output relays switch back after the time delay of tvMIN and stop the pump. The whole process starts again when the level reaches the “MAX” probe.

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20.06.22 en / 583A

Technical Data Input

Technical Data General Data

Setting range of the

fluid resistance:

2 … 450 k (response value)

Setting:

On logarithmically divided absolute scale

Switching point hysteresis: Approx. 4 % (at 450 k)

… 15 % (at 2 k) of the set value

Voltage and temperature

influence:

< 2 % of the set value

Max. cable length to the

probes:

Set value

Cable length

(at 100 nF/km)

450 k

50 m

100 k

200 m

35 k

500 m

10 k

1500 m

5 k

3000 m

Max. sensing voltage:

Approx. AC 10 V

(internally generated)

Max. sensing current:

Approx. AC 1.5 mA

(internally generated)

Response and release times

tvMIN, tvMAX:

0.2 … 20 s for both output relays separate settable

Setting on logarithmically-divided

absolute scale

Auxiliary Circuit

Auxiliary voltage UH:

AC 24, 42, 110, 230 V DC 24 V

Voltage range of UH

AC:

0.8 … 1.1 UN

DC:

0.85 … 1.25 UN

Nominal power consumption

AC:

Approx. 2 VA

DC:

Approx. 1 W

Frequency range:

45 … 400 Hz

Output

Contacts

IL / SL 9151.12, MK 9151N.12: 2 x 1 changeover contact

Thermal current Ith:

4 A

Switching capacity

IL / SL 9151:

To AC 15

NO contact:

5 A / AC 230 V

IEC/EN 60947-5-1

NC contact:

2 A / AC 230 V

IEC/EN 60947-5-1

To DC 13:

2 A / DC 24 V

IEC/EN 60947-5-1

MK 9151N:

To AC 15

NO contact:

3 A / AC 230 V

IEC/EN 60947-5-1

NC contact:

1 A / AC 230 V

IEC/EN 60947-5-1

To DC 13:

1 A / DC 24 V

IEC/EN 60947-5-1

Electrical life

IL / SL 9151:

IEC/EN 60947-5-1

To AC 15at 1 A, AC 230 V: 2 x 105 switching cycles

MK 9151N:

IEC/EN 60947-5-1

To AC 15 at 1 A, AC 230 V: 1.5 x 105 switching cycles

Short circuit strength

max. fuse rating:

4 A gG / gL

IEC/EN 60947-5-1

Mechanical life:

30 x 106 switching cycles

Operating mode:

Continuous operation

Temperature range:

Operation:

– 20 … + 60 °C

Storage:

– 25 … + 70 °C

Altitude:

2000 m

Clearance and creepage

distances

Rated rated impulse voltage voltage /

pollution degree

IEC 60664-1

IL / SL 9151:

Input / Auxiliary Circuit: Input / output circuit:

6 kV / 2 (at UH = DC 24 V: 1kV) 6 kV / 2

MK 9151N:

Input / Auxiliary Circuit: Input / output circuit:

4 kV / 2 (at UH = DC 24 V: 1 kV) 4 kV / 2

Auxiliary / output circuit

A1-A2 (AC):

4 kV / 2

EMC

Electrostatic discharge:

8 kV (air)

IEC/EN 61000-4-2

HF irradiation

80 MHz … 2.7 GHz:

10 V / m

IEC/EN 61000-4-3

Fast transients:

2 kV

IEC/EN 61000-4-4

Surge voltages

Between

wires for power supply:

1 kV

IEC/EN 61000-4-5

Between wire and ground:

2 kV

IEC/EN 61000-4-5

HF wire guided:

10 V

IEC/EN 61000-4-6

Interference suppression:

Limit value class B

EN 55011

Degree of protection

Housing:

IP 40

IEC/EN 60529

Terminals:

IP 20

IEC/EN 60529

Housing:

Thermoplastic with V0 behaviour

according to UL subject 94

Vibration resistance:

Amplitude 0.35 mm,

frequency 10 … 55 Hz, IEC/EN 60068-2-6

Climate resistance:

20 / 060 / 04

IEC/EN 60068-1

Terminal designation:

EN 50005

Wire connection:

IL / SL 9151:

2 x 2.5 mm2 solid or

2 x 1.5 mm2 stranded ferruled

DIN 46228-1/-2/-3/-4

Min. cross section:

0,6 mm

Insulation of wires

or sleeve length:

10 mm

MK 9151N:

1 x 4 mm2 solid or

1 x 2.5 mm2 stranded ferruled or

2 x 1.5 mm2 stranded ferruled

DIN 46228-1/-2/-3/-4

Min. cross section:

0.5 mm2

Abisolierlänge der Leiter:

8 mm

Wire fixing:

IL / SL 9151:

Flat terminals with self-lifting

clamping piece

IEC/EN 60999-1

MK 9151:

Box terminal with wire protection

Fixing torque:

0.8 Nm

Mounting:

DIN rail

IEC/EN 60715

Weight

IL 9151:

Approx. 165 g

SL 9151:

Approx. 192 g

MK 9151N:

Approx. 180 g

Dimensions

Width x height x depth IL 9151: SL 9151: MK 9151N:

35 x 90 x 59 mm 35 x 90 x 98 mm 22.5 x 90 x 98 mm

CCC-Data

Nominal voltage UN: MK 9151N:

AC 24, 42, 110, 230 V DC 24 V

Switching capacity To AC 15 NO contact:

1.5 A / AC 230 V IEC/EN 60947-5-1

Technical data that is not stated in the CCC-Data, can be found
nfo in the technical data section.

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20.06.22 en / 583A

Standard Type

IL 9151.12 2 … 450 k AC 230 V 0.2 … 20 s

Article number:

0049135

· Settable response value: 2 … 450 k

· ·

Auxiliary voltage UH: Response and release

AC delay: 0.2

230 V … 20 s

· 2 output relays with 1 changeover contact each

· With safe separation

· Width:

35 mm

Application Example

12 11 14 22 21 24

A1

12 14

22 24

A2

11

21

MIN MAX COM X1 X2

SL 9151.12 2 … 450 k AC 230 V 0.2 … 20 s

Article number:

0051552

· Settable response value: 2 … 450 k

· ·

Auxiliary voltage UH: Response and release

AC delay: 0.2

230 V … 20 s

· 2 output relays with 1 changeover contact each

· With safe separation

· Width:

35 mm

Niveau
M6634_b
IL 9151, SL 9151 with safe separation according to IEC/EN 61140, IEC/EN 60947-1

MK 9151N.12 2 … 450 k AC 230 V 0.2 … 20 s

Article number:

0054100

· Settable response value: 2 … 450 k

· ·

Auxiliary voltage UH: Response and release

AC delay: 0.2

230 V … 20 s

· 2 output relays with 1 changeover contact each

· Width:

22.5 mm

Variants MK 9151N.12/001: MK 9151N.12/002:

Time delay, when level drops under setting value Time delay, when level rises over setting value

Ordering example for variants

12 11 14 22 21 24

A1

12 14

22 24

A2

11

21

MIN MAX COM X1 X2

K1

K2

M11101

MK 9151 N .12 /00_ 2 … 450 k

AC 230 V 0.2 … 20 s
Response and release delay Auxiliary voltage Response value Variant, if required Contacts Type

Application as contact protection relay, e.g. for two reed contact switches (K1, K2).

Accessories OA 5640:
5

Standard probe Article number: 0016045

21

M5670
140

Stainless steel immersion electrode, Temperature range: 0 … + 60 °C, Weight: Approx. 0.1 kg Wire connection: 1.5 mm2 stranded wire with sleeve without plastic collar Stripping length: 10 mm Fixing torgue: 0.6 Nm
16

E.Dold&SöhneGmbH&Co.KG·D-78120Furtwangen · Bregstraße 18 · Phone +49 7723 654-0 · Fax +49 7723 654356

dold-relays@dold.com·www.dold.com

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20.06.22 en / 583A

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