OTT SDI-12 Radar Level Sensor Instruction Manual

OTT SDI-12 Radar Level Sensor

Product Information

Specifications

• Product Name: Radar Level Sensor OTT RLS
• Order Number: 63.108.001.9.2
• Firmware Version: V 2.00.0
• Manufactured Date: January 2015 onwards

Product Usage Instructions

1. Installing the OTT RLS
   Follow these steps for proper installation:

2. Choose a suitable mounting location based on provided criteria.

3. Ensure proper power supply according to the notes.

4. Use suitable cable types for RS-485 interface if applicable.

5. Mount the OTT RLS securely.

6. Connect the OTT RLS to a datalogger using either an SDI-12 interface or a 4-20 mA interface based on requirements.

7. SDI-12 Commands and Responses
   Understand the standard and advanced SDI-12 commands for efficient operation.

8. Carrying out Maintenance Work
   Regular maintenance is essential for optimal performance:

   • Follow the maintenance instructions provided in the manual.
   • Check and clean the sensor components periodically.

9.   Troubleshooting
   If you encounter issues, refer to the troubleshooting section in the manual for guidance on resolving common problems.

Frequently Asked Questions (FAQ)

• Q: Can I use the OTT RLS with any datalogger?
  A: Yes, you can connect the OTT RLS to any datalogger using either an SDI-12 interface or a 4-20 mA interface as described in the manual.

• Q: What should I do if I need to dispose of an old unit?
  A: Follow the instructions provided in the manual for proper disposal of old units to prevent environmental damage.

Operating instructions Radar Level Sensor OTT RLS

• These Operating Instructions, version 04-0124 describe the OTT RLS firmware version V 2.00.0 used in equipment manufactured as of January 2015. They are only valid for OTT
• RLS radar sensors with the order number 63.108.001.9.2!
• Please note : When you want to swap an existing OTT RLS manufactured before July 2009 for a new unit, the datalogger configuration should be checked and modified as applicable.
• In such a case, please contact OTT HydroService.
• We reserve the right to make technical changes and improvements without notice.

Scope of supply

OTT RLS

• Radar sensor OTT RLS, two part swivel mount (consisting of device and wall brackets with 4 M8 Allen bolts) with SDI-12-, RS-485- and 4 … 20 mA interface
• Installation kit (4 x wood screws 6 x 40 mm; 4 x plastic plugs S8)
• Double open-ended wrenches size 10 x 13
• Operating instructions
• Factory acceptance test certificate (FAT)

Order numbers

• OTT RLS Radar sensor OTT RLS 63.108.001.9.2
  • Accessories Connection cable 97.000.039.9.5
  • twisted-pair design
  • PVC, black
  • 2 x 2 x 0,5 mm2
  • AWG 20
• Connection cable 97.000.040.9.5
  • twisted-pair design
  • PVC, black
• 2 x 2 x 0,75 mm2
  • AWG 19
• OTT RLS bridge mounting 63.105.025.3.2
• Mounting aid for attaching the OTT RLS to a bridge
  • For side mounting
  • Height according to customer requirements
  • Distance to bridge according to customer requirements
  • Including angle bracket for attachment from above
• OTT USB/SDI-12 Adapter 65.050.002.9.2
• For temporarily connecting OTT sensors to a PC with
  • SDI-12 or RS-485 interface
  • Including 1 USB connection cable. USB connector type A to USB type B; 3 m

Basic safety information

1. Markings and symbols used in the instruction
   • This bullet point indicates an instruction relating to a specific action.
   • This bullet point indicates an item in a list.
   • This bullet point indicates a sub-item in a list.

Remarks:

• Information on easier and more efficient work
• Further information
• Definition

Please note: …
Information that prevents potential damage or malfunction on the OTT RLS.

Explanation of safety information used

The safety information used in these operating instructions is classified according to the nature and severity of a particular hazard. The hazard level defined is indicated by the signal word “WARNING” and a pictogram (orange triangle) in these operating instructions.

WARNING Warning of a hazardous situation with a medium level of risk

• The safety information specifies the nature and source of the hazard.
  • If you fail to carry out the specified actions, the hazardous situation can result in death or serious injuries.
  • Action to prevent the hazardous situation!
  • Action to prevent the hazardous situation!

Note the following for safe and trouble-free operation

• Read these operating instructions before using the OTT RLS for the first time!

• Make yourself completely familiar with the installation and operation of the OTT RLS! Retain these operating instructions for later reference.

• The OTT RLS is used for contactless level measurement of surface waters. Only use the OTT RLS in the manner described in these operating instructions!

• For further information  ➝ see Chapter 4, Introduction.

• Note all the detailed safety and warning information given within the individual work steps.

• Never use the OTT RLS in areas where there is a danger of explosion.
  For further information ➝ see Chapter 5, Installing the OTT RLS.

• Note that the electric installation of the OTT RLS may only be done by a professional. For further information ➝ see Chapter 5, Installing the OTT RLS.

• Protect the power supply connection with a fuse (0.250 ampere, blowing speed: fast). For further information ➝ see Chapter 5, Installing the OTT RLS.

• It is essential to comply with the electrical, mechanical and climatic specifications given in the Technical Data section. For further information ➝ see Chapter 11, Technical data.

• Do not make any changes or retrofits to the OTT RLS. If changes or retrofits are made, all guarantee claims are voided. Furthermore, the radio approval required for its operation is void!

• Have a faulty OTT RLS inspected and repaired by our repair center. Never make any repairs yourself under any circumstances. For further information ➝ see Chapter 8, Repair.

• Dispose of the OTT RLS properly after taking out of service. Never put the OTT RLS into the normal household waste. For further information ➝ see Chapter 10, Note about the disposal of old units

 Radio frequency approval

The OTT RLS with the order number 63.108.001.9.2 may not be used within the countries of the European Union, USA and Canada. It has no radio approval for these regions!
Please use the OTT RLS with order number 63.109.001.9.2 for applications in the countries of the European Union, USA and Canada!
Please note: Before installing the OTT RLS, please check whether operation of a radar sensor with a transmission frequency of 24.1 GHz (transmission power < 5 mW) is permitted in the measuring site region.

Introduction

• The OTT RLS radar sensor is used for contactless measurement of the levels of surface water.
• Operation of the OTT RLS is based on pulse radar technology. The transmitting antenna emits short radar pulses on 24.1 GHz. The separate receiver antenna receives the pulses reflected from the water and uses them to determine the distance between sensor and water surface: the time taken by the radar pulses from transmission to reception is proportional to the distance between sensor and water surface. The actual water level of the waterway is then calculated automatically, if required, by the radar sensor. To do this, on initial startup there is the possibility of inputting the relevant measurement mode and a reference value.
• Three standardized electrical interfaces are available for connecting the OTT RLS to a datalogger or peripheral devices: 4 … 20 mA, SDI-12 and RS-485 (SDI-12 protocol).
• The radar sensor can be configured via the SDI-12 transparent mode of a data-logger or via the OTT USB/SDI-12 Adapter (accessory; SDI-12/RS-485 interface). When using the 4 … 20 mA interface, it is possible to scale the measurement out- put to a smaller measuring range.
• The transmission antenna has a beam width of approx. 12 °. The resulting sensor beam can be seen in the depiction in Figures 2 and 3 and the table in Chapter 5.1.
• The OTT RLS includes a swivel mount that allows the sensor housing to be mounted parallel (longitudinal and lateral axis) with the water surface, even when the sensor is mounted on a slanted surface. A waterproof terminal area can be found under a removable screw cover for attaching the sensor cable.

Fig. 1: Overview of radar sensor OTT RLS.

• If the RS-485 interface is used, the length of cable between radar sensor and data – logger can amount up to 1000 meters · 3,300 ft. Using the SDI-12 interface, the maximum length of cable is 100 m · 330 ft.
• Provided that the unit has been mounted correctly according to the operating instructions, the complete radar sensor is flood proof with IP 67 rating (diving bell principle).
• Fig. 2: Application example 1: Mounting the OTT RLS on a bridge.
• The projection of the sensor beam onto the water surface is virtually round.
• Fig. 3: Application example 2: Mounting the OTT RLS on an auxiliary construction, e.g. metal stand with mounting plate.

Installing the OTT RLS

• WARNING Danger of explosion due to spark formation and electrostatic discharge
• The use of the OTT RLS in explosive atmospheres can lead to the danger of ignition of this atmosphere. An explosion resulting from this involves the risk of very severe material and personal damage.  discharge
• The use of the OTT RLS in explosive atmospheres can lead to the danger of ignition of this atmosphere. An explosion resulting from this involves the risk of very severe material and personal damage.
• Never operate the OTT RLS in explosive areas (e. g. in sewers). The OTT RLS is not equipped with EX-protection (EXplosion protection).

Please note:

• The electrical installation of the OTT RLS may only be undertaken by qualified persons (e.g. a specially trained electrician)!
• Never operate several radar sensors (OTT RLS, third-party products) at one measuring site at the same time! Simultaneous operation leads to inaccurate measurements or measurement errors. If necessary, synchronise the sample intervals of the radar sensors to each other (factory setting OTT RLS measuring time: approx. 20 seconds).

Criteria for selecting a suitable mounting location

• Possible mounting locations are, for example, bridges and auxiliary constructions directly above the waterway section to be measured.
• The minimum distance between lower edge of the sensor and water surface must be 0.4 m · 1.3 ft (dead area in which no useable measurement is possible).
• Select a mounting point high enough so that measurement is possible even with high water levels.
• The mounting point must be steady. Vibrations and movement of the mounting point must be avoided. Bridges are affected by movements of several centimeters as a result of load changes and temperature movements. If pillars are available, the sensor can be mounted to a stable positioned pillar with a suit-able spacer.
• The water surface must be as smooth as possible in the area of the sensor beam. Avoid turbulent areas, areas where foam is created, surge areas and waterway sections where obstructions or bridge piers cause changes in the water level. The measurement result cannot be used if there is ice or snow on the water surface!
• Choose a mounting location that does not become dry at low water levels.
• Stations subject to very rapid changes in water level are not suitable. With factory setting the OTT RLS averages its measurement result over a measuring time of approx. 20 seconds. For special applications the default measuring time can be reduced (see advanced SDI-command aOXM!; chapter 6.2).
• The area within the sensor beam (see Figures 2 and 3) must be completely free of obstructions. Table for approximating the size of the sensor beam:

The diameters given are minimum sizes. Where possible, select an area free of obstruction that is clearly larger.

• Avoid large metal surfaces near the sensor beam (reflections from these sur faces can distort the measurement result).
• The climate specifications in the technical data must be kept to at the mounting location.
• Stilling wells are unsuitable as a mounting location.
• The OTT RLS cannot be used to measure wave height.

Notes on power supply
The OTT RLS requires a power supply of 5.4 … 28 V direct current of type
12/24 VDC (e. g. a battery or mains connection with galvanically isolated low safety voltage).
The OTT RLS is immediately ready for operation after connecting the power supply.
Please note:

• Secure the power supply cable (terminal 1 of the screw terminal strip) with a fuse (0.250 ampere, reaction time: fast)!
• When using solar panels, we recommend the use of an overvoltage protection device.

Suitable cable types when using the RS-485 interface
The maximum length of the connecting cable is 1,000 m · 3,300 ft. Recommended cable type: Twisted-pair cable; unshielded (alternatively: shielded). The wires intended for the power supply can be twisted pair, but do not have to be. Types of OTT cable which can be used (see accessories)

• up to 500 m · 1,650 ft length of connecting cable: 2 x 2 x 0,5 mm2; approx. AWG 20 (flexible wires)
• 500 to 1000 m · 1,650 to 3,300 ft length of connecting cable: 2 x 2 x 0,75 mm2; AWG 19 (flexible wires)

Mounting the OTT RLS

• Please note: Ensure no moisture enters the connection area when the screw cover is open! If the connection area gets moist there is increased danger of corrosion of the electric contacts.
• Assembling the swivel mount (see also Annex C)

Mounting surface: concrete or masonry

• Make four holes (Ø 8 mm · 5/16″ / 43 mm · 1.7 ft deep) using a hammer drill (use wall bracket as a template).
• Insert the four plastic plugs supplied into the holes.
• Attach the wall bracket using the four wood screws supplied.
• Insert housing bracket (without sensor) into wall bracket and lightly tighten the hex bolts A (see fig. 5).

Mounting surface: auxiliary construction, e. g. metal stand with mounting plate

• Drill four holes (Ø 7 mm · 9/32″) in the mounting plate (use wall bracket as a template).
• Attach the wall bracket e. g. using four hex bolts (M6) and nuts.
• Insert housing bracket (without sensor) into wall bracket and lightly tighten the hex bolts A (see fig. 5).

Preparing the cable gland

• With a cable diameter of 7.0 … 11.0 mm, remove inlet: Insert screwdriver vertically into the seam and lever out the inlet. See Figure 4.
• Insert the connecting cable.

Mounting the radar sensor

• Remove screw cover.

• Insert connecting cable from OTT RLS to datalogger through cable gland.

• Remove insulation from connecting cable.

• With flexible wires: put end caps on the wires.

• Connect the connecting cable to the terminal block. Take note of Chapters 5.5 and 5.6 and Appendices A and B. If required, the terminal strip can be pulled
  out for connecting

• Retighten connecting cable as necessary.

• Tighten the tightening nut of the cable gland (torque for tightening nut: 6 Nm).

• Screw on the screw cover and tighten firmly by hand.

• Insert sensor into housing bracket and lightly tighten the hex bolts B (see fig. 5).

• Align the housing parallel (longitudinal and lateral axis) with the water surface
  using a bubble level.

• Tighten the hex bolts B (housing shell) carefully (see fig. 5).

• Tighten the hex bolts A (wall/housing brackets) carefully (see fig. 5).

• Check alignment of the OTT RLS once more.

Fig. 4: OTT RLS – connection area.
Clamping range of the cable gland: with inlet ➝ 4.0 to 7.0 mm without inlet ➝ 7.0 to 11.0 mm

Please note: The alignment of the sensor parallel to the water surface must be carried out as accurately as possible! Deviation from the parallel alignment leads to a linearity error!

Connecting the OTT RLS to any datalogger using an SDI-12interface

• Connect the OTT RLS to an SDI-12 input of the datalogger. Follow the data logger handbook as you do this. Refer to Figure 6 for the connection assignments of the OTT RLS. The maximum length of the connecting cable is 100 m · 330 ft. Recommended wire cross-section: 0.5 mm2 · AWG 20. With separate voltage supply and point-to-point connection (no SDI-12 bus operation) a cable length of up to 300 m · 985 ft is possible.

Fig. 6: Connecting the OTT RLS to any datalogger using an SDI-12 interface. (Standard SDI-12 wiring via three-wire connecting cable).

You will find the SDI-12 commands for the OTT RLS in Chapter 6, SDI-12 commands and responses.

Connecting the OTT RLS to any datalogger using a 4 … 20 mA interface

• Connect the OTT RLS to a 4 … 20 mA input of the datalogger. Follow the data- logger handbook when doing this. Refer to Figure 7 for the connection assign-ments of the OTT RLS. The maximum connecting cable length/recommended wire cross-section: depending on the amount of voltage supply and the size of the burden (load resistor). Please note that the ohmic resistance of the connecting cable together with the eventually existing burden do not exceed the max. allowed load resistance (see Chapter 5.7)!
• Please note : The 4 … 20 mA interface of the OTT RLS is passive. If needed the supply for the current loop must be injected by wire-linking the supply voltage. For this case the minimum supply voltage is 9.6 Volt.
• Remark : To connect the OTT RLS using the 4 … 20 mA interface, a 4-wire cable is required. If the OTT RLS is also to be configurable via SDI-12 commands, use 5-wire (cable length up to 100 m) or 6-wire cable (cable length up to 1000 m).

Fig. 7: Examples for connecting the OTT RLS to any datalogger via the 4 … 20 mA interface.

• Left: supplying the loop current from the datalogger.
• Right: supplying the loop current to the OTT RLS supply voltage using wire bridges.

Determining the maximum load resistance at the 4 … 20 mA interface

• The load resistance (burden + ohmic resistance of the connection cable) connected to the OTT RLS must not exceed a specific maximum value. This value depends on the level of the supply voltage of the OTT RLS. If the load resistance is greater, the output current can no longer be evaluated. Smaller load resistances are allowed.
• Read off the maximum load resistance for your power supply from the following diagram.
•  Example: Power supply 18 volt ➝ max. load resistance 450 ohm.
• The OTT RLS delivers an output current corresponding to the measured value for a load resistance of up to 450 ohm.
• Dimension the connected electrical circuit accordingly. Check the input resistance of the connected peripheral device for this purpose.

Figure 8: Diagram to determine the maximum load resistance as a function of the power supply.

• Minimum power supply : 9.6 V Maximum power supply: 28 V
• Resistor tolerance : 0.1 %/15 ppm (burden = load resistor).

Notes on using the 4 … 20 mA interface

• Switching behaviour of the 4 … 20 mA interface After switching on the supply voltage, it takes approx. 20 seconds until the loop current takes on a value proportional to the water level. (In the first 20 seconds, the loop current is between 3 and 4 mA.) Afterwards, the radar sensor updates the loop current every 20 seconds.
• In case of failure, the loop current is also between 3 or 4 mA. For more information, please refer to Chapter 9, “Interface Status Messages/Output”.
• Please note: The 4 … 20 mA interface cannot be used parallel to the SDI-12 or RS-485 interfaces. (Exception: temporary configuration of the OTT RLS with SDI-12 commands.)

Note on using the RS-485 interface

• The RS-485 interface is designed and tested to be used with the OTT dataloggers. In such a case, the transmission protocol used within the physical RS-485 interface is the SDI-12 protocol. Connecting the OTT RLS to OTT netted using the RS-485 interface: ➝ refer to Appendix A, option B.
• OTT will not provide any performance guarantee when you use the RS-485 inter-face to connect the OTT RLS unit to a third-party datalogger!

SDI-12 commands and responses

Standard commands
All SDI-12 standard commands (SDI-12 version 1.1) are implemented in the OTT RLS: The following SDI-12 standard commands are relevant for the operation of the OTT RLS:

1. do not use this command if OTT RLS is connected to a datalogger via the 4 … 20 mA interface! OTT RLS would consequently interrupt the continuous measuring operation which is needed for the 4 … 20 mA interface.
2.  dependent on the units set (advanced command aOSU!)

More information on the SDI-12 standard commands can be found in the document SDI-12; A Serial-Digital Interface Standard for Microprocessor-Based Sensors; Version 1.4 (see Internet page www.sdi-12.org).
Advanced SDI-12 commands
All advanced SDI-12 commands begin with an “O” for OTT. With these commands, it is possible to configure the OTT RLS using the transparent mode of a datalogger or with the OTT USB/SDI-12 Adapter (accessory).

Please note : Changing the unit deletes any set reference or offset value !

With the commands setting/reading the lower/upper limit you can scale the available measuring range of an OTT RLS to a smaller range. Where you do not require the whole measuring range, this has the advantage that a higher resolution for the 4 … 20 mA interface can be achieved. Example: 16 mA measurement span stands for 5 m · 16 ft of water level change available (e.g. lower limit = +10,000 m · +33,00 ft; upper limit = +15,000 m · +49.00 ft; see Fig. 9).
Fig. 9: Scale the measured value output of the 4 … 20 mA interface down to a smaller range.

 Carrying out maintenance work

The OTT RLS radar sensor is almost maintenance free. No setting or calibration work is necessary. There are likewise no parts that need replacing regularly.
Carry out the following maintenance work at regular frequencies based on the coal circumstances:

• Check the OTT RLS for dirt (e. g. thick, dewy spider’s webs or insect nests can lead to impairment of the measured results). In this case, carefully clean the sensor (if necessary use commercial, gentle and non-erasing cleaners and a soft sponge). At the same time, ensure that the setting of the swivel mount does not change.
• Check for obstructions in the measurement beam (for example, for flotsam or branches of trees and bushes growing into this area). In this case, remove all obstructions.
• Check the plausibility of the measured values by comparing with a second sensor or with a staff gauge.

Please  note: Never open the housing of the OTT RLS (exception: connection area)! There are no adjustment or operating elements inside the housing.

Repair

• With a device defect, use Chapter 9, Troubleshooting to see if you can resolve the problem yourself.
• In case of device defects, please contact the repair center of OTT:
  • OTT HydroMet GmbH Repair center
  • Ludwigstrasse 16
  • 87437 Kempten ·
  • Germany Telephone +49 831 5617-433
  • Fax +49 831 5617-439
  • [email protected]

Please note : Only have a defective OTT RLS checked and repaired by the OTT HydroMet repair center. Never make any repairs yourself under any circumstances. Any repairs or attempted repairs carried out by the customer will result in the loss of any guarantee rights.

Troubleshooting

Sensor does not respond to the SDI-12 interface

• Fuse in the power supply input side defective?
  • ➝ Replace fuse.
• Sensor correctly connected to a datalogger with SDI-12 input?
  • ➝ Correct connection assignment.
• Polarity of the power supply reversed?
  • ➝ Correct connection assignment.
• Power supply < 5.4 VDC or > 28 VDC?
  • ➝ Correct level of voltage supplied (check the length and cross-section of the connection cable).
• Is the power supply direct current?
  • ➝ Only operate sensor with direct current.

20 mA signal not present

• Sensor correctly connected to a datalogger or peripheral device to 4 … 20 mA input (check polarity)?
  • ➝ Correct connection assignment.
• 4 … 20 mA current loop correctly supplied through datalogger or OTT RLS (internal/external supply)?
  • ➝ Correct connection assignment.
• Power supply < 9.6 VDC or > 28 VDC?

Measured value varies or is not present

• Sensor (front plate) dirty?
  • ➝ Carefully clean the sensor; see Chapter 7, Carrying out maintenance work
• Obstruction in the measurement beam?
  • ➝ Remove obstructions.
• Sensor aligned at right angles to the water surface?
  • ➝ Correct sensor alignment.
• Mounting location of the sensor steady (e.g. bridge movement)?
  • ➝ Optimize mounting location.
• Large metal surfaces near the sensor beam (e.g. piling)?
  • ➝ Optimize mounting location.

Status messages/output of interfaces

value below or above measuring range

+32| 3.5 mA| internal error ➝ device defect; see Chapter 8, Repair

1. response to commands aM!, aM1! and aD0!

Note about the disposal of old units

• Dispose of the OTT RLS properly after taking out of service.
• Observe the regulations valid in your country for the disposal of electronic devices.
• Never put the OTT RLS into the normal household waste.
• Used materials
  see Chapter 11, Technical Data

Technical Data

1. at +20 °C · +68 °F ambient temperature: 1013 mbar · 29.9 inHg air pressure; 45 % to 65 % relative humidity; ideal reflector; without interfering reflector in the sensor beam; measuring time: 20 seconds
2. power consumption of OTT RLS with SDI-12, RS-485 or externally supplied 4 … 20 mA interface
3. condensation on the front plate of the antenna (Radom) can disturb measuring accuracy

Annex A – Connecting the OTT RLS via SDI-12 or RS-485 interface to OTT netDL

There are two ways to connect the OTT RLS:

• Method A: using the SDI-12 interface (protocol and physical interface: SDI-12).
• Method B: using the RS-485 interface
• (SDI-12 protocol via physical RS-485 interface).
• Recommendation: method B (longer range, more resistant to faults)
• Method A: Connecting the OTT RLS via the SDI-12 interface (protocol and physical interface: SDI-12). The maximum length of the connecting cable is 100 m · 330 ft.
• Recommended wire cross-section: 0.5 mm2 · AWG 20:
• Connect the OTT RLS to the IP Datalogger OTT netDL as shown in Figure 10  (left). Take note of the operating instructions for the OTT netDL.
• Method B: Connect OTT RLS using the physical RS-485 interface (SDI-12 protocol via physical RS-485 interface). Refer to Chapter 5.3 for the maximum connecting cable length and the recommended wire cross-section:
• Connect the OTT RLS to the IP Datalogger OTT netDL as shown in Figure 10 (right). Take note of the operating instruct ions for the OTT netDL.

Fig. 10: Connecting the OTT RLS to      OTT netDL using an SDI-12 interface.

The letters above the screw terminal strip identify the possible connections on the OTT netDL.

Configuring the OTT netDL for the OTT RLS with SDI-12 interface

• Create an OTT netDL channel with SDI-12 Recorder or OTT SDI RS485 function
• block (serial sensors tab). Apply the following settings:

Fig. 11: Adjusting the operating parameters of the OTT netDL SDI-12 Recorder function block. The function block OTT SDI RS485 is set in the same way.

• Terminal block

• OTT netDL OTT SDI RS485:

  • C 1-2 (default)

• OTT netDL S DI-12 Recorder:

  • C 3-4 (default)

• Sensor address

  • Terminal block (screw terminal strip) of the OTT netDL to which the OTT RLS unit is connected.
    SDI-12 bus address. Each address may only be allocated once to an SDI-12 bus feed! (Checking/setting: see operating instructions OTT netDL, Chapter SDI-12 transparent mode; alternatively with OTT USB/SDI-12 Adapter). Factory setting of the OTT RLS: 0 Identifies which value from the OTT RLS is recorded in this channel.

• Value no.

  • In M! Measurement Mode: Level/Distance value = 1, Status of the last measurement = 2
  • In M1! Measurement Mode: Status of the last measurement = 1, Signal/noise ratio = 2

• Measurement mode

  •  M! for Level/Distance value and Status of last measurement or
    – M1! for Advanced status of the last measurement The OTT RLS unit does not support Concurrent Mode!

• Concurrent Mode

  • Instantaneous value : Upon an instantaneous value request (via LCD display and jog shuttle), the OTT netDL unit sends a com-mand to the OTT RLS unit to start a current measurement. Until this measurement is complete, the LCD display refers to the last measured value (or the instantaneous value last displayed, whichever is the most recent one).
  • On the display, this is identified by an “s” to the right of the channel number (sensor number). After completing the measurement, the new measured value appears without additional identification.
  • Shows the last measured value of the sensor (measured value of the last sample interval) for an instantaneous value request. On the display, this is identified by an “s” to the right of the channel number (sensor number), (also refer to the OTT netDL IP Datalogger Operating Instructions, Chapter 9.1). For an OTT RLS unit (extended measuring time), the setting is useful for a short sample interval.
  • Allocation of the additional OTT RLS measured values –those not recorded on this channel
  • to virtual terminals.

• Value no./ Virtual terminal ID

  • In the relevant Channel function blocks, adjust the required units and number of digits after the decimal place (m: 3; cm: 0; ft: 2; status information: 0).

Remarks:

• To record the measurements and status information of an OTT RLS, two channels in the OTT netDL are thus necessary. The first channel contains the function block SDI-12 Recorder or OTT SDI RS485 as the input signal. The second channel contains a function block Virtual Sensor (V02) as the input signal. If the recording of status information is not required, no entry is necessary in the Value no./Virtual terminal ID field.
• The measuring mode M1! supplies extended status information. If required, this can also be recorded in an additional channel with function block SDI-12 Recorder/OTT SDI RS485.
• You will find further information on the used SDI-12 commands and responses in Chapter 6, SDI-12 commands and responses.
• Please note : The OTT RLS makes the measurement results available a maximum of 25 seconds after the SDI-12 command aM!!

Annex B – Connecting the OTT RLS via 4 … 20 mA interface to OTT netDL

• Connect the OTT RLS to the OTT netDL IP Datalogger as shown in Figure 12.  Take note of the operating instructions for the OTT netDL. Maximum connecting cable length/recommended wire cross-section: depending on the amount of voltage supply. Please note that the ohmic resistance of the connecting cable does not exceed the max. allowed load resistance (see Chapter 5.7)!

Fig. 12: Connecting the OTT RLS to OTT netDL using a 4 … 20 mA interface

• The OTT netDL unit requires the optional Analog Input Card.
• The letters above the screw terminal strip identify the possible connections on the OTT netDL.

Configuring the OTT netDL for OTT RLS with 4 … 20 mA interface

• Create an OTT netDL channel including a U/I/Pt100/… functional block
• (Analog sensors tab).
• Apply the following settings:

Fig. 13: Setting operating parameters of the OTT netDL function block I 4-20 mA.

Annex C – Dimensions of wall bracket/position of fixing bores

Annex D – Declaration concerning to the health of the user

If necessary, you can download the current version of the “Declaration concerning to the health of the user” of the OTT RLS from our website as PDF file: “www.ott.com/resources

• OTT HydroMet GmbH Ludwigstrasse 16 87437 Kempten
• Germany Phone +49 831 5617-0
  • Fax +49 831 5617-209
  • [email protected]
  • www.otthydromet.com
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