Labkotec OMS-1 Oil Separator Alarm Device
General Information
OMS-1 is an alarm device for monitoring the thickness of the oil layer accumulating in an oil separator. The system consists of the OMS-1 control unit, the OMS sensor, and a cable joint.
Oil separator supervision with the OMS-1 alarm device
The function is based on the measurement of the electrical conductivity of the surrounding liquid – water conducts electricity much better than oil.
The LED indicators, push button, and interfaces of the OMS-1 control unit are described in Figure 2.
OMS-1 control unit – features
Installation
OMS-1 Control Unit
The OMS-1 control unit can be wall-mounted. The mounting holes are located in the base plate of the enclosure, beneath the mounting holes of the front cover.
The connectors of the external conductors are isolated by a separating plate. The plate must not be removed. The cover of the enclosure must be tightened so that the edges touch the base frame.
Only then does the push button function properly, and the enclosure is tight.
Before installation, please read the safety instructions in chapter 6!
OMS-1 alarm device installation.
OMS Sensor
The OMS sensor should be installed as described in Figure 3. The sensor gives an alarm when the upper electrode is in oil. Please check the correct installation depth also from the instructions of the oil separator.
Cable joint
Connections of the sensor cable inside the cable joint are explained in Figure 3. If shielded cable is used cable shields and possible excess wires need to be connected to the same point in galvanic contact.
Please make sure that the sensor and cable between the OMS-1 control unit and the sensor do not exceed the maximum allowed electrical parameters – see Chapter 7, Technical data. The IP rating of the cable joint is IP68. Make sure that the cable joint is closed properly.
Notice in cabling: Risk of electrostatic charging! If the sensor cable must be extended and there is a need for equipotential grounding, it should be done with the junction box LJB2. The cabling between the OMS-1 control unit and the junction box should be done with a shielded twisted pair instrument cable. Maximum cable length is 100 m.
Operation
The operation of the alarm device should always be checked after the installation. Also, check the operation always when emptying the separator or at least once every six months.
Functionality Test
- Immerse the sensor in water. The device should be in normal mode.
- Lift the sensor in the air or oil. An Oil alarm should be generated (see chapter 3.1 for a more detailed description).
- Clean up the sensor.
- Immerse the sensor back into water. The alarm should go off after a delay of 10 seconds.
A more detailed description of the operation is provided in Chapter 3.1. If the operation is not as described here, check connections and cabling. If necessary, contact a representative of the manufacturer.
Operation Modes
Normal mode – no alarms
- The sensor is totally immersed in water
- The main LED indicator is on.
- Other LED indicators are off.
- Relay is energized.
Oil alarm
- The sensor is immersed in oil. (The sensor gives an alarm when the upper electrode is in oil.)
- The main LED indicator is on.
- The Oil Alarm LED indicator is on.
- Buzzer on after 10 10-second delay.
- Relay de-energize after 10 sec delay.
(Note. The same alarm takes place when the OMS sensor is in the air.)
After removal of an alarm, the Oil Alarm LED indicator and buzzer will be off, and the relay will be energized after 10 10-second delay.
Fault alarm
- Sensor cable break, short circuit, or a broken sensor. The main LED indicator is on.
- Sensor circuit, Fault LED indicator is on after 10 10-second delay.
- The buzzer is on after 10 10-second delay.
- The relay de-energizes after 10 10-second delay.
Reset of an alarm
- When pressing the Reset/Test push button.
- The buzzer will go off.
- If the buzzer is not reset, it goes off automatically after three days.
Function Test
The test function provides an artificial alarm, which can be used to test the function of the OMS-1 alarm device and the function of other equipment which are connected to OMS-1 via its relay. Attention! Before pressing the Reset/Test button, make sure that the change of relay status does not cause hazards elsewhere!
Normal situation
- When pressing the Reset/Test push button:
- Oil Alarm and Fault LED indicators are immediately on.
- The buzzer is immediately on.
- Relay de-energize after 2 seconds of continuous pressing.
- When the Reset/Test push button is released:
- LED indicators and buzzer go immediately off.
- Relay energize immediately.
Alarm on
- When pressing the Reset/Test push button for the first time:
- The buzzer will go off.
- When pressing the Reset/Test push button after that:
- The fault LED indicator is immediately on.
- Oil Alarm LED indicator remains on.
- Buzzer remains on. If it has been reset earlier, it will return to being on.
- When the Reset/Test push button is released:
- The device returns right away to the preceding status.
Fault alarm on
- When pressing the Reset/Test push button:
- The device does not react to the test at all.
Troubleshooting
- Problem: MAINS LED indicator is off
- Possible reason: The Device doesn’t get the supply voltage.
- To do
-
- Measure the voltage between poles N and L1. It should Labkotec OMS-1 Oil Separator Alarm Device be 230 VAC ± 10 %.
- Problem: No alarm when the sensor is in oil or air, or the alarm will not go off
- Possible reason: Sensor is dirty.
- To do
-
- Clean up the sensor and check the operation again.
- Problem: FAULT LED indicator is onÂ
- Possible reason: Resistance in the sensor circuit is too high (cable break or out of the connector) or too low (cable in a short circuit).
- To do
-
- Disconnect the sensor’s [+] wire and measure the resistance between the [+] and [-] wires. The measured resistance should be 45-51 kΩ.
- If it is possible, measure also the resistance between the [+] wire and the sensor’s upper electrode. The measured resistance should be 1,1 – 1,3 kΩ.
- If the resistance values in items 2 and 3 Labkotec OMS-1 Oil Separator Alarm Device are correct, then the OMS-1 control unit is defective; otherwise problem is in the cab or n inn the sensor.
Repair & Service
The easiest way to check the operation is to lift Labkotec OMS-1 Oil Separator Alarm Device the sensor out of the separator and then put it back in. In case of queries, please get in touch with Labkotec Oy’s service.
Technical Data
The table below indicates the connecting values in explosion group IIB.
OMS-1 electrical parameters
Dimensional drawing of the OMS sensor
APPENDIX 1. OMS System drawing
EU Declaration of Conformity
Product
- Control unit and conductivity-based sensor Lokaset 20 control unit SET/LV or SET/L sensor
Manufacturer
- Labkotec Oy Myllyhaantie 6 FI-33960 Pirkkala Finland
Directives
- The product is in accordance with the following EU Directives: 2014/30/EU Electromagnetic Compatibility Directive (EMC), 2014/35/EU Low Voltage Directive (LVD), 2011/65/EU Restriction of Hazardous Substances Directive (RoHS)
Standards
- EMC: EN IEC 61000-6-3:2021, EN IEC 61000-6-2:2019, EN IEC 61000-3-2:2019; LVD: EN 61010-1:2010/A1:2019/AC:2019-04; RoHS: EN IEC 63000:2018.
Signature
- Signed for and on behalf of Labkotec Oy. Pirkkala 31.8.2021 Janne Uusinoka, CEO Labkotec Oy
Customer Service
- E-mail:Â labkonet@labkotec.fi
- Tel:Â +358 29 006 6066.
- Address:Â Myllyhaantie 6, FI-33960 Pirkkala, Finland
© 2025 Labkotec.fi.
FAQs
What is the Labkotec OMS-1 used for?
It helps guarantee adherence to environmental rules and stops oil from leaking into drainage systems by warning the user when the oil layer inside the separator reaches a critical level.
How does the OMS-1 detect oil accumulation?
The OMS-1 employs a capacitive sensor that can discriminate between water and oil, usually the Labkotec SET/OS2 or SET/OSK2. It keeps an eye on the interface between the two liquids and sounds an alarm if the oil layer rises above the predetermined level.
Is the OMS-1 system compliant with environmental standards?
Indeed. The OMS-1 conforms to the oil separator EN 858-1 and EN 858-2 requirements. For controlled discharge monitoring, local environmental authorities frequently demand it.
What kind of power supply does the OMS-1 require?
The usual operating voltage for the OMS-1 is 230 VAC (mains voltage). For low-voltage applications, there can be versions with 24 VDC.
Can the OMS-1 distinguish between oil, water, and sludge?
The OMS-1 sensor uses dielectric differences to differentiate between water and oil layers.
Is the OMS-1 suitable for use in explosive (ATEX) environments?
The OMS-1 is compatible with some ATEX-certified sensor models.
Where can I find support, spare parts, or documentation?
You may access all of the resources, such as sensor accessories, spare parts, and updated manuals, at www.labkotec.com or by contacting your authorised Labkotec dealer.