KROHNE SWSILBT01 User Manual

Data sheet

Liquid Level Switch

Type LLS 4000/4000U

			The LLS 4000/4000U liquid level switch is
			designed to detect the state (gas or liquid) of the
			refrigerant in front of the sensing head, while
			installed in a wide range of refrigeration
			applications.
			The LLS level switch comes in 2 variants, LLS 4000
			and LLS 4000U. They are identical except for the
			connector thread interface to the system. The LLS
			4000 is provided with G3/4" thread, while the LLS
			4000U is provided with NPT 3/4" thread.
			The LLS 4000/4000U liquid level switch is based
			on the proven reflectometry measuring
			technology(microwave level measurement)
			adapted specifically for the new LLS 4000/4000U
			switch.
			LLS 4000/4000U liquid level switches can be used
			to control the liquid level of many different
			refrigerants in vessels, accumulators, receivers,
			standpipes, etc.
			The switches are normally installed in a pair of
			two, controlling the upper liquid level and the
			lower liquid level.
			The level switch includes a relay that switches by
			change in refrigerant state. The on site
			configuration of the LLS allows the normally
			open/closed relay setting depending on the
			desired correlation.
			For SIL applications a SIL2 version is available
			with blocked configuration (not configurable).
			All configuration and readings from the LLS
			switch are performed through Bluetooth and a
			downloadable special Danfoss app.
Features	•	Plug and play liquid level switch	• Approvals: CE, PED, EMC, RED, ROHS, SIL2, FCC,
	•	Easy installation and minimum or no need for	( EAC, IC pending)
	configuration		• Conforms to:
	• Convenient communication with all units via		Telecommunications Directive RED 2014/53/EU.
	Bluetooth and a Danfoss app
			Low voltage directive 2014/35/EU.
	•	SIL2 compliant version
			EMC directive 2014/30/EU.
	• 2 commonly used connection variants
			ROHS 2011/65/EU
	•	Maintenance free

• Replacement of electronic part without removing mechanical part (no opening to refrigerant)

• Applicable for ammonia and commonly used H(C)FCs

• Well proven reflectometry measuring principle

© Danfoss | DCS (ms) | 2020.02

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Data sheet | Liquid Level Switch, type LLS 4000/4000U

Contents	Features . . . . . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	1
	Product concept/applications .	. . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3
	Connection types . . . . . . . . . . . .	. . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4
	Measuring principle . . . . . . . . . . .	. . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4
	Electrical installation/connection . . . . . . . . . . . . . . .		. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	5
	LED light indicators . . . . . . . . . .	. . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	5
	Configurable parameters . . . .	. . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	5
	Ordering . . . . . . . . . . . . . . . . . . .	. . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	7
	Dimensions and weights . . . . . .	. . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. 7
	Maintenance/service & calibration precautions . . .		. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	8
	Bluetooth communication . . . . .	. . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	8
	Bluetooth configuration . . . . . .	. . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	9
	Technical data . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	10
	Safety/ Approvals . . . . . . . . . . . . .	. . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	11

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© Danfoss | DCS (ms) | 2020.02

Data sheet | Liquid Level Switch, type LLS 4000/4000U

Product concept/ applications

To control if a liquid level is within predefined allowed limits, two LLS 4000 are installed in an upper and a lower limit position respectively. By this setup the liquid level is between the two level switches and the lower switch will sense liquid, while the upper will sense gas.

In case the liquid level moves outside the limits, one of the switches will sense opposite and switch the built-in relay. This relay switch function should be used for alarm settings. This is made easy when connected to the system PLC.

	SVA	SVA
			AKS 4100
SFA					EKE
+DSV
					347
		SVA
		LLS 4000	LLG
					ICF 25-6-5A
		LLS 4000
			SNV			SVA
			SVA
SCA-X			SCA-X		SVA
				FIA
					BSV
		BSV
FIA	SNV				SNV	SVA
				SNV
						QDV
	RT		RT			15
	260A		260A	SNV
SNV	SNV
					SNV
	SVA		SVA

Upper

LLS 4000/U

Liq. Level

Lower

LLS 4000/U

The LLS can be used wherever liquid levels of ammonia and certain H(C)FC refrigerants must be controlled.

The LLS comes in 2 versions:

-A standard version, which is applicable for most refrigeration or processing plants, and is fully configurable regarding type of liquid and relay setting.

-A SIL2 version applicable for SIL compliant process plants. This version is non-configurable regarding relay setting (see section: Configurable

parameters) and is intended specific as the upper level switch.

© Danfoss | DCS (ms) | 2020.02

AI323832972563en-000101 | 3

Data sheet | Liquid Level Switch, type LLS 4000/4000U

Connection types	Beside the 2 versions the LLS also comes with 2
	different thread types , LLS 4000 and LLS 4000U.
	They are identical except for the connector
	thread for installation to the system. The LLS
	4000 is provided with G3/4" thread, while the LLS
	4000U is provided with NPT 3/4" thread.

For connection to the actual part of the system appropriate weld connectors are needed. NPT connectors are widespread available, while Danfoss offers weld connectors for G3/4" thread as accessory.

Please note geometric restrictions below.

		Weld
LLS 4000	G 3/4”	connector
LLS 4000U	NPT 3/4”
		max
		45 mm
		1.8 in	min
			25 mm
			1 in

Measuring principle	The measurement principle of the LLS is based
	on reflectometry with a 4.9 GHz to 6.2 GHz
	linear sweep (Microwave switch technology).
	The reflected signal is characterized by a
	resonance frequency. The resonance frequency
	in air is taken as a reference (fref). When the
	sensing element is in contact with the liquid,
	the resonance frequency is shifting to a lower
	frequency. This is due to the change of the
	dielectric constant of the medium.

The point level switch monitors the resonance frequency and indicates whether the sensing element is surrounded by liquid or gas.

The figure below shows the reference frequency with air (dielectric constant εr=1) in front of the sensing element and with a liquid dielectric constant εr> 1.35.

PR

∆f ~ εr

with	without
liquid	liquid

f

4.9 GHz fliquid fref 6,2GHz

© Danfoss | DCS (ms) | 2020.02

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