On water service ...



Explosion proof type available (on request)


The Model ODL-1600 monitors a water surface for the presence of an oil film floating on the surface. The instrument projects a laser beam onto the water surface and measures the differences in the reflection properties between water and oil.

This model is the most recent in a series of oil on water monitors. These have been field proven over decades and are used in a wide variety of installations worldwide. These instruments include the Models ODL-12 and ODL-20.

The design of the model ODL-1600 is the result of decades real world experience and features many new enhancements including faster signal processing, improved optical design and continuous scanning laser system. These design enhancements enable the Model ODL-1600 to offer improved oil detection even for non-ideal water surfaces such as those with bubbles present.

This model complements our existing range. If installation in hazardous areas is required, we recommend our intrinsically safe Model SODL-20 version. The Model SODL-20 has official certification showing compliance with the relevant IEC standards. Please refer to a separate specification sheet for information on this particular version.



Product name Oil on water monitor (non explosion proof version)
Model ODL-1600
Measurement object Oil slick floating on water surface or dry surface (floor)
Measurement method Reflectance of visible light
Sensor distance

0,3 - 3,0 m above water or floor surface (0,3 - 5,0 m for smooth water surfaces - for example located indoors)

Light source Class 2 semiconductor laser diode (red)
Configuration Detector and transmitter housed in separate enclosures
Ingress protection IP 65
Ambient conditions Temperature: -10 - 50° C
Humidity: 5 - 95 % RH
Sample temperature No freezing
Output signals 4 - 20 mA max load 600 Ohms (additional alarm status selectable) It is also possible to set analogue output to ODL-20 compatibility mode (normal conditions: 18 mA, oil detected 20 mA, instrument malfunction 16 mA)
Contact switching output signals Total 6 contacts available ("a" contact x 5, "c" contact x 1) Oil alarm, under maintenance (ST BY mode setting), Detection error (water surface detection error, reflected light error, ambient light error), Instrument error (laser output error, internal temperature error) power failure (selectable closed or open during power failure) Contact rating: 30 VDC, 0,1 A
Digital communication system - Based on RS 485 (isolated)
- Available Baud rates: 2400, 4800, 9600, 19200, 38400, 57600
- Protocol: MODBUS / RTU
- Data length: 8 bits
- Parity: select from None, Odd, Even
- Stop bits: 1 Bit
- Data order: Big Endian
Operating power 100 - 240 VAC ± 10 %, 50/60 Hz
Power consumption Approx. 10 VA (normal), approx. 15 VA (max).
When optional heater is installed consumption will be approx. 30 VA
Weight Transmitter: approx. 2,2 kg
Detector section: approx. 14 kg
External dimensions Transmitter: approx 181 (w) x 180 (h) x 95 (d) mm
Detector: approx 240 (diameter) x 443 (l) mm
Construction materials Transmitter: die cast aluminium Detector: die cast aluminium
Surface finish Metallic silver
Electrical connections Transmitter: six cable glands for 6 - 12 mm diameter cable, G1/2 threaded connections when gland removed Detector: two cable glands for 6 - 12 mm diameter cable, G1/2 threaded connections when gland removed
Connecting cable lengths Transmitter to detector: max 100 m (power and communication cable)
Transmitter to receiving device: max 100 m (digital communication)



The reflectance of light from an oil film is greater than that of water. When an oil film is present on a water surface, it generated a "glistening" effect. From this property, the presence of oil can be detected by applying a light beam of constant intensity to the water surface and then measuring the intensity of the reflected light.

The detector contains a semiconductor laser diode, a laser scanner and a photodiode light sensor. The light output from the laser tube is scanned across the water surface periodically across the x-y axis. The light that is reflected back by the water surface is captured by a parabolic mirror and focused on to a sensor located at the focal point of the mirror.

The signal from the light sensor is processed by the micro electronics in the transmitter. From the processed signal it can be determined whether an oil film is present or not. The transmitter provides output signals indicating the detection status such as contact switching signals, analogue signals,…

Water level height variation

Mirror & light sensor


The instrument comprises a detector and transmitter. The detector and transmitter continuously communicate. The raw detection signal and diagnostic information are sent from the detector to the transmitter. The transmitter provides local status display and generates output signals for onward transmission to an external plant control system or external receiving device. The transmitter allows set up of operating parameters such as detection mode and alarm setting … As an option, two detectors can share a single transmitter. In this configuration the transmitter communicates with each detector individually and provides individual alarm and analogue output signals corresponding to each detector (max 6 contacts switching points).


1. Display

The transmitter displays information on calibration, oil film detection status, raw light intensity, self-diagnostics and error conditions.

2. Oil Detection Modes

The transmitter allows the detector to be set up for particular water surface conditions such as still, smooth surfaces or unstable surfaces with waves and bubbles, … The transmitter allows the operator to establish a suitable set up for the particular installation conditions.

3. Analogue Output Signals

A 4 - 20 mA output signal is available representing the light intensity signal. As an additional function, the analogue output can also be set to indicate alarm status of the instrument (oil detection, instrument malfunction). It does this by changing the analyser output to an out of scale value (21 mA, 3 mA). Thus a single analogue signal can transmit three detection conditions (normal operation with raw intensity signal, instrument malfunction and oil alarm).

4. Contact Switching Output Signals

A total of six contact switching signal are available. These can be configured by the operator to represent alarm and self diagnostic information. The available signals are as follows:
- Oil film detection
- Under maintenance (ST-BY mode)
- Detection error (water surface detection error, reflected light error, ambient light error)
- Instrument malfunction (laser output trouble, internal temperature alarm)
- Power failure (open or closed contact available)

5. External Device Communication

Digital communication with external devices is available using MODBUS protocol from the RS 485 output signal.

6. Optional Dual Detector Capability

It is possible to connect two detectors to a single transmitter enablining the monitoring of two different locations simultaneously.

7. Detection History Stored in Memory

Detection parameters are stored in memory together with date and time of detection. This data can be re-called by the operator. The historical data can be used to evaluate instrument performance and assist in fine tuning the sensitivity set-up, …



(1) The detector should be mounted within 0,3 to 3,0 m from the water surface for normal water conditions. In ideal conditions (for example smooth water surfaces located indoors) the distance can be increased to within 0,3 to 5,0 m. When evaluating installation locations consider water level changes, these must be within the distances given above. Avoid mounting too close to the water surface in order to avoid splashing and potential damage due to immersion during unexpected flooding, heavy rain, …

(2) Install the analyser at a location where the water flows smoothly. Avoid locations where there is turbulence.

(3) Install the analyser at the location where the monitoring surface will not be subjected to direct rainfall or direct wind disturbance, because a severely rippled water surface may make it difficult for oil film detection. For such locations, protection against direct rainfall or wind disturbance will be required.

(4) Avoid installing the detector in locations where dead leaves or other debris may accumulate on the water surface. These may affect water flow characteristics and cause detection problems.

(5) Avoid locations where sunlight may disturb detection. If strong sunlight causes detection problems, move the detector to a shady location or install a sun shade.

(6) Strong, direct sunlight may cause high temperatures inside the instrument enclosures. When the instrument is installed in locations subject to strong sunlight, protect with an appropriate sun shade.

(7) Install the instrument in a location where vibrations and mechanical shocks are minimised. Secure a space around the analyser and scaffolding if necessary for a safe and easy access during maintenance.

(8) Avoid locations where there is rising mist due to high water temperature. If this is unavoidable, supplying a gentle airflow will effectively clear the vapour away.

(9) If using the instrument to monitor liquid leakage on dry surfaces (such as floors…), ensure that the surface is level. A sloping surface will not reflect the light from the laser beam correctly and cause detection problems. Select a part of the surface where any leaked liquid will form a smooth liquid film. If the dry surface is excessively shiny, place a non-reflective surface over it such as a rubber mat, …





December 2009 - the manufacturer reserves himself the right to modify technical specifications without prior notice.

ISMA on water sevice ...