KN5101 - Capacitive level sensor IFM - Free user manual and instructions

Product Type	Capacitive Level Sensor
Brand	IFM
Model	KN5101
Main Function	Capacitive detection of bulk material (dry solids or liquids) through a non-metallic wall
Supply Voltage	18-36 V DC
Output	PNP/NPN switching (depending on version) + clogging output (fc-output)
Sensitivity Range	Adjustable via push-button or programming input (pin 2)
LED Indicators	Green (on), yellow (output active), red (error / unsafe zone)
Mounting	Directly into the tank wall (housing KNM30BSA...) or externally (housing KNM30NSA...)
Housing Material	Stainless steel
Protection Degree	IP67
Ambient Temperature	-25°C to +80°C
Special Functions	Empty and full adjustment, lock/unlock, clogging detection
Maintenance	Periodic cleaning, functional check via LEDs
Safety	Disconnect power before any connection
Spare Parts	Contact the manufacturer
General Information	User manual available for free download at notice-facile.com

Frequently Asked Questions - KN5101 IFM

How to adjust the KN5101 level sensor?

To adjust the sensor, briefly press the push-button to perform an 'empty' adjustment (empty tank) then, if necessary, a 'full' adjustment (full tank). You can also use the programming input (pin 2) by applying a pulse of appropriate duration. The 'empty' adjustment is usually sufficient.

What does the flashing red LED mean?

The flashing red LED indicates an error during adjustment or lock/unlock. It can also flash if the 'empty' and 'full' signals are too close. In this case, briefly press the button to confirm and repeat the adjustment.

How to lock and unlock the device?

To lock, press the push-button for at least 10 seconds: the green LED flashes slowly then faster, then turns off. To unlock, repeat the same action: after 10 seconds, all LEDs turn off briefly then the device is unlocked.

What to do if adjustment is not possible (red LED flashes)?

If the red LED flashes after an adjustment, it means the 'empty' and 'full' signals are too close. Briefly press the push-button to confirm, then repeat the adjustment. Make sure the tank is empty or full according to the selected adjustment.

Can liquids be detected with this sensor?

Yes, the KN5101 can detect liquids, but only through a non-metallic wall (external mounting). For liquids, use the mounting with the KNM30NSA... housing fixed outside the tank.

What is the difference between 'empty' and 'full' adjustment?

The 'empty' adjustment calibrates the sensor on an empty tank. The 'full' adjustment fine-tunes the sensitivity on the bulk material. The 'empty' adjustment is usually sufficient; the 'full' adjustment is useful for difficult applications requiring optimal reserve capacity.

How to mount the sensor on a non-metallic tank?

Fix the KNM30NSA... housing to the outside of the non-metallic tank. The sensor detects the material through the wall. Ensure the wall is clean and without metallic coating.

What to do if the clogging output (fc-output) is active?

The active clogging output (red LED on) indicates an unsafe zone: either the full tank where detection is uncertain, or the empty tank where the signal has changed (e.g., fouling). Clean the sensor and repeat the adjustment.

Can I use this sensor for conductive materials?

Yes, the capacitive principle allows detection of conductive (e.g., liquids) and non-conductive materials. However, for conductive liquids, external mounting is recommended and specific adjustment may be necessary.

How to reset the sensor after an incorrect adjustment?

Perform a new 'empty' adjustment: the switching thresholds will be reset to initial values, erasing previous adjustments. You can then perform a 'full' adjustment if necessary.

USER MANUAL KN5101 IFM

Capacitive level switch

Détector de niveau

capacitif

KN

Function and features

The capacitive level switch controls the level in vessels. It detects if target medium is present or not and provides a switched signal.

• Adjustable to the target medium by means of a programming button or by an electrical signal on the function check output.

LED's red, yellow, green

Installation

Units of the type KNM30BSA... should be mounted into the vessel wall.

The sensor is in contact with the target medium.

Suitable for dry target medium.

Units of the type KNM30NSA... should be mounted outside the vessel. The sensor detects the target medium through the vessel wall.

Suitable for both dry and liquid target media.

Only for non-metallic vessels.

Electrical connection

Disconnect power before connecting the unit. Connect according to the indications on the type label.

Setting

• With target medium absent

The setpoint is adjusted while the vessel is empty. When target medium is detected, the sensor's output switches. The switch-on and switch-off points are automatically generated.

• With target medium present

For most applications setting the sensor while the vessel is empty is sufficient. You can, if you wish, make an additional adjustment with the target medium present (e.g. to obtain an optimum excess gain for special applications).

*You can adjust the setpoint via pin 2 (fc output).

(signal length = duration of pressing the button)

Type FPKG: (+U_B) to pin 2; type FNKG: (-U_B) to pin 2.

The setpoint values made with an empty vessel are not overwritten by automatic setting while the vessel is full. You can update adjustment with the vessel full as often as you wish. (Automatic setting with the vessel full will return the "full" setting to the factory default.)

If adjustment is not possible (e.g. "empty" signal strength and "full" signal strength are almost the same), the red LED flashes after setting (in addition the function check output provides a 2Hz signal).

Press the button briefly (= acknowledgement) and repeat setting.

Locking / Unlocking:

1	Press for at least 10s*	→	At first the green LED flashes slowly, then faster. After 10s it goes out. The unit is locked.
2	Press for at least 10s*	→	After 10s all LED's go out for a short time. The unit is unlocked and the LED's indicate the current operating status.

*You can also lock/unlock the unit via pin 2 (fc output).

(signal length = duration of pressing the button)

Type FPKG: (+U_B) to pin 2.

Type FNKG: (-U_B) to pin 2.

Operation

Check whether the unit functions properly. Indication by LED's and by the function check output:

LED green	unit is ready for operation
LED yellow lit = output is switched flashing = output is short-circuited
LED red + fc output	ON = uncertain range: - when the vessel is full: target medium is not safely detected - when the vessel is empty: the “empty” signal has changed since the last setpoint adjustment (e.g. due to excessive build-up of deposits). flashing + 2Hz signal of the fc output = error in setting or locking / unlocking.