IFM LW2720 Operating Instructions Manual
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IFM LW2720 Operating Instructions Manual

Electronic level sensor
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Electronic level sensor
LW2720

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Summary of Contents for IFM LW2720

  • Page 1 Operating instructions Electronic level sensor LW2720...

  • Page 2: Table Of Contents

    LW2720 Electronic level sensor Contents Preliminary note ............. .
  • Page 3 Electronic level sensor LW2720 10.1 Troubleshooting incorrect level readings ........35 10.1.1 Level too high / too low .

  • Page 4: Preliminary Note

    LW2720 Electronic level sensor 1 Preliminary note You will find instructions, technical data, approvals and further information using the QR code on the unit / packaging or at www.ifm.com. 1.1 Symbols used Requirement Instructions Reaction, result [...] Designation of keys, buttons or indications...

  • Page 5: Safety Instructions

    Electronic level sensor LW2720 2 Safety instructions • The unit described is a subcomponent for integration into a system. – The system architect is responsible for the safety of the system. – The system architect undertakes to perform a risk assessment and to create documentation in accordance with legal and normative requirements to be provided to the operator and user of the system.

  • Page 6: Intended Use

    LW2720 Electronic level sensor 3 Intended use The unit continuously monitors the level of liquids in tanks without contact. Bulk materials are detected depending on their properties (conical heaps, grain size, dielectric constant, etc.). 3.1 Application area Non-contacting radar technology is ideally suited for food and beverage applications as it is maintenance-free, has a top-down installation that reduces the risk of leakages, and is unaffected by process conditions such as density, viscosity, temperature, pressure and pH.

  • Page 7: Restriction Of The Application Area

    Electronic level sensor LW2720 CIP process: The unit withstands standard CIP routines and SIP routines up to 140 °C. Optimisation of cleaning agent storage. 3.2 Restriction of the application area • The unit is not suitable for some bulk materials (e.g. coffee beans) due to their often very low dielectric constant.

  • Page 8: Items Supplied

    Product information with safety instructions and reference to the complete operating instructions at www.ifm.com. In addition, the following is necessary for installation and operation: • Mounting material (Ò Accessories) Only use accessories from ifm electronic gmbh! The optimum function is not ensured when using components from other manufacturers. Available accessories: www.ifm.com.

  • Page 9: Function

    Electronic level sensor LW2720 5 Function 5.1 Measuring principle The measuring principle of the unit is Frequency Modulated Continuous Wave (FMCW). The unit continuously emits electromagnetic waves in the GHz range with a constantly varying frequency towards the medium surface. Since the transmitter continuously changes the frequency of the transmitted signal, there will be a difference in frequency between the transmitted and the reflected signals (Ò...

  • Page 10: Foam And Turbulence

    The IODDs necessary for the configuration of the unit, detailed information about process data structure, diagnostic information, parameter addresses and the necessary information about the required IO-Link hardware and software can be found at www.ifm.com. 5.3 Outputs The unit generates output signals according to the parameter setting. Two outputs are available: •...

  • Page 11: Switching Function

    Electronic level sensor LW2720 100% (20mA) I [mA] AEP2 ASP2 (ASP2) (4mA) (AEP2) Fig. 2: Analogue output blind zone current zone with reduced accuracy level recommended measuring range rising curve ([ASP2]<[AEP2]) zero point = reference point dropping curve ([ASP2]>[AEP2]) Note the tolerances and accuracies during the evaluation of the analogue signal (Ò...

  • Page 12: Defined State In The Event Of A Fault (Alert Mode)

    LW2720 Electronic level sensor Fig. 3: Single-point mode Fig. 4: Two-point mode level time hysteresis Window function: u [SSC1 Config. Mode] must be set to [Window]. The width of the window can be set by means of the difference between [SSC1 Param. SP1] and [SSC1 Param.

  • Page 13: Simulation Function

    Electronic level sensor LW2720 unit continues to work in normal operation. If, however, it is not received again in sufficient strength within the delay time, the unit passes into the alert mode and output OUT2 changes into the defined state.

  • Page 14: Mounting

    LW2720 Electronic level sensor 6 Mounting CAUTION With high process temperatures, parts of the unit may heat up. w Risk of burns u Do not touch the unit. u Protect the housing against contact with flammable substances and unintentional contact. u Allow the unit and process adapter to cool down before maintenance.

  • Page 15: Inclination

    Electronic level sensor LW2720 6.2 Inclination u Mount the unit vertically (90°) to ensure a good echo from the medium surface. u Maximum inclination (1): 3° (Fig. Inclination). 90° Fig. 7: Inclination 6.3 Non-metallic tanks Non-metallic tanks are, for example, fibreglass tanks. Nearby objects outside the tank may cause disturbing radar echoes as such materials may allow radar waves to pass through.

  • Page 16: Nozzle Requirements

    LW2720 Electronic level sensor 6.5 Nozzle requirements u To allow the radar waves to propagate undisturbed, the specified nozzle dimensions should be observed (Ò Fig. Nozzle dimensions and table). u The inside of the nozzle must be smooth (i.e. avoid bad welding, rust, or deposit).

  • Page 17: Notes On The Use According To 3-A

    Electronic level sensor LW2720 u To avoid dead space adhere to the dimensions: L < (D - d) d = 25 mm 1: Leakage port 2: Seal 6.6.2 Notes on the use according to 3-A® u Make sure that the sensor is integrated into the system according to 3-A.

  • Page 18: Place The O-Ring, Grease The Thread

    LW2720 Electronic level sensor u Before installing, carefully remove the protective cap. u Be careful not to scratch or otherwise damage the antenna. 6.8.2 Place the O-ring, grease the thread The matching O-ring (EPDM) is supplied with the adapter. More O-rings are available as accessories.

  • Page 19: Premount The Adapter For Pipe Fittings

    Electronic level sensor LW2720 6.8.3 Premount the adapter for pipe fittings u Slide the coupling nut up over the bottom of the unit. u Make sure that the O-ring is mounted in the groove of the unit. u Screw the adapter onto the unit until it is hand-tight.
  • Page 20 LW2720 Electronic level sensor CAUTION During the welding operation, the adapter and the welding aid can increase in temperature to over 65 °C (149 °F). w Risk of burns u Let the components of the welding aid and weld-in adapter cool down before removal.

  • Page 21: Mount The Unit In The Tank

    Electronic level sensor LW2720 Welding operation: u During welding and the following cooling phase the unit must not be in place. u During welding, avoid overheating of the adapter and observe sufficient cooling phases. u While welding, the adapter must not warp.

  • Page 22: Mount The Unit With Pipe Fitting

    LW2720 Electronic level sensor u Lower the unit with the mounted Tri Clamp adapter onto the tank nozzle. u Tighten the clamp to the recommended torque (Ò Manufacturer’s installation instructions ). 6.9.2 Mount the unit with pipe fitting u Place a suitable gasket on top of the tank flange.

  • Page 23: Mount The Unit With Varivent® Adapter

    Electronic level sensor LW2720 6.9.3 Mount the unit with VARIVENT® adapter u Make sure that the O-ring is mounted in the groove of the unit. u Screw the VARIVENT adapter onto the unit (not shown). Tighten to the recommended torque (Ò...
  • Page 24 LW2720 Electronic level sensor u Remove the O-ring (1) from the unit before mounting. Otherwise, the O-ring may come off due to the missing end stop and enter the process. In this case, the seal is formed by the rear flat seal (2) (non-hygienic).

  • Page 25: Electrical Connection

    Electronic level sensor LW2720 7 Electrical connection The unit must be connected by a qualified electrician. The national and international regulations for the installation of electrical equipment must be adhered to. Supply voltage SELV, PELV according to the technical data sheet.

  • Page 26: Parameter Setting

    LW2720 Electronic level sensor 8 Parameter setting Changing parameters during operation can influence the function of the plant. u Make sure that there will be no malfunctions or dangerous operation in your plant. The device parameters are set via the IO-Link interface. For this, an IO-Link master, IO-Link parameter setting software (Ò...

  • Page 27: Adjustable Parameters

    Electronic level sensor LW2720 u Set the parameters. Before parameter setting, familiarise yourself with all the parameters. u Check if the unit has accepted the parameter settings. If necessary, read the unit again. u Check whether the unit operates correctly.
  • Page 28 LW2720 Electronic level sensor Parameter Options Explanation Access SSC1 Param. SP2 Setting range: 0...14.995 m Set point 2 for SSC1 (switching signal chan- nel 1). Only available with window function and in two- point mode. Set point 2 must be smaller than set point 1. If set point 2 is set higher than set point 1, this will be rejected by the device software.
  • Page 29 Electronic level sensor LW2720 Parameter Options Explanation Access FOU2 [On] = analogue output switches to a val- Response of OUT2 in alert mode. ue > 21 mA in alert mode. Switching output switches ON in alert mode. [OFF] = analogue output switches to a value < 3.6 mA in alert mode.
  • Page 30 LW2720 Electronic level sensor device reference point (lower edge/sealing edge of the process connection) reference height (measuring range) zero point (lower end of the measuring range, tank bottom is lower) tank offset Fig. 15: Tank offset If the tank bottom does not correspond to the zero point: u Enter the distance between the zero point and the tank bottom (D) as [Tank offset].

  • Page 31: System Commands

    Electronic level sensor LW2720 upper blind zone disturbing echo of object 100% (20 mA) of the analogue range detection threshold medium surface echo 150 300 450 600 750 900 Fig. 16: Upper blind zone / detection threshold Nozzles or other objects close to the antenna may cause disturbing reflections. Such reflections can be blocked out by configuring an upper blind zone (A).
  • Page 32 LW2720 Electronic level sensor u Set the unit: (parameter [uni] = [m]). u Set the tank height: Parameter [Reference height] = [8.000] m. w The tank bottom may be interpreted as a low level. In this case: u Correct the tank height and configure a tank offset.

  • Page 33: Operation

    Electronic level sensor LW2720 9 Operation 9.1 Function check After power-on the unit is in the operating mode. It carries out its measurement and evaluation functions and generates output signals according to the set parameters. u Check whether the unit operates correctly.
  • Page 34 • Verify operating voltage is between 18-30 V. Maintenance required – Cleaning. Product build-up on the antenna. • Clean the antenna. For further information, please refer to the IODD description (www.ifm.com) or to the context-specific parameter descriptions of the used parameter setting software.

  • Page 35: Troubleshooting

    Electronic level sensor LW2720 10 Troubleshooting 10.1 Troubleshooting incorrect level readings 10.1.1 Level too high / too low level time actual level measured level Possible cause: • Incorrect tank geometry configuration. Recommended actions: • Verify the tank geometry parameters are configured correctly, especially the reference height.

  • Page 36: Measured Value Drops When Level Close To Antenna

    LW2720 Electronic level sensor Possible cause: • Disturbing object in the tank. 15° Recommended actions: • Analyse the echo peaks and check the detection threshold. • If possible, remove the disturbing object or change the device position. • Rotate the unit in steps of about 15 degrees.

  • Page 37: Measured Value Fluctuates

    Electronic level sensor LW2720 level time actual level measured level Possible cause: • The level is within the upper blind zone and a false echo is interpreted as the level. Recommended actions: • Check the setting of the upper blind zone.

  • Page 38: Measured Value Is Occasionally Unstable

    LW2720 Electronic level sensor 10.1.5 Measured value is occasionally unstable level time actual level measured level Possible cause: • The level is close to a suppressed false echo. Recommended actions: • If possible, remove the disturbing object or change the device position.

  • Page 39: Measured Value Correct At 0% (4 Ma) But Incorrect At 100% (20 Ma)

    Electronic level sensor LW2720 10.1.7 Measured value correct at 0% (4 mA) but incorrect at 100% (20 mA) level time actual level measured level Possible cause: • Analogue end point (parameter [AEP2]) is not set correctly. Recommended actions: • Correct parameter [AEP2]. 10.1.8 Incorrect measured value when level is above 50%...

  • Page 40: Level Measurement Is Lost In An Empty Tank

    LW2720 Electronic level sensor level time actual level measured level Possible cause: • A strong tank bottom echo is interpreted as the level. Recommended actions: • Verify the reference height is configured correctly. • With very low dielectric media: Reduce the reference height and configure a tank offset.

  • Page 41: Alert Mode When Level Close To Tank Bottom

    Electronic level sensor LW2720 10.1.11 Alert mode when level close to tank bottom When the level is near the sloped tank bottom, the device enters the alert mode. level time actual level measured level Fig. 17: Possible cause: • Radar signal is scattered to the side by the sloped tank bottom.

  • Page 42: Maintenance, Repair And Disposal

    LW2720 Electronic level sensor 11 Maintenance, repair and disposal The unit can be unscrewed from the adapter for cleaning. u Check the unit and the mounting adapter at regular intervals and tighten again, if necessary. u Only use suitable tools with plastic wrench flats for wetted surfaces.

  • Page 43: Factory Setting

    Electronic level sensor LW2720 12 Factory setting Parameter Factory setting User setting Access Application Specific Tag Function Tag Location Tag Reference height Initial value Tank offset 0 (m) Upper blind zone 0 (m) out1/out2 SSC1 / I (4…20 mA) dS1/dS2 0 (s) dr1/dr2 0 (s) SSCx* Param.

  • Page 44: Appendix

    LW2720 Electronic level sensor 13 Appendix 13.1 Approvals and certificates The EU declaration of conformity, approvals and country-specific certificates are available at: www.ifm.com Approval-related notes: Ò Packing slip...

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