Oxygen (O2) Gas Detector RO2 025 September 2021

Features

• Range 0-25 % vol.

• Output
2 x 4-20 mA or 0-10 Vdc, user settable

• RS485, Modbus RTU protocol

• Power supply 24 Vdc (11-30 Vdc)

24 Vac as option
RO2 025 • Electrochemical sensor

• Response time T90

15 seconds

• IP65 protection of enclosure

• Microporous PTFE dust filter ensure

IP65 also for the sensor

• Sensor life time > 2 years

(for 5 years lif time see other type RO2L 025)

Ordering
_______________________________________________
RO2 025 DM Type no. Description
_______________________________________________

RO2 025 Oxygen (O2) gas detector

range 0-25% vol.

Options

24VAC Integrated 24 Vac power supply module

DM Duct mounting type

RSP3 Remote sensor probe, 3 meters cable

RSP10 Remote sensor probe , 10 meters cable

RLCD Remote LCD display,

wall mount enclosure 115x65x40 mm
RO2 025 RSP3

Ordering example

Oxygen (O2) gas detector with remote LCD display and with
integrated 24 Vac power supply module is with type number
RO2 025 RLCD 24VAC.

Note

When the option Integrated 24 Vac power supply module

(24VAC) is supplied, the power supply can be 24 Vac or 24 Vdc.

Ventilation Control Products Sweden AB - Phone: +46-31-811666 - E-mail: info@vcp.se - Web: www.vcp.se
 Oxygen (O2) Gas Detector RO2 025 September 2021

Alarm limits for decreasing concentration of gas is set to 18-19%.

Other reasons why oxygen levels can fall are among others:

• Combustion of something which consumes oxygen

• Corrosion of something that reduces the oxygen concentration
• Oxygen consumption due to breathing in dense areas.

Problems usually arise in confined spaces such as tanks, tunnels, etc.

Oil- and gas industry

The normally closed spaces like tanks, containers, pontoons,

etc.. corrosion may have contributed to making oxygen levels drop to low values.

A worker entering such an area may die immediately.

Therefore, it is important to first check the oxygen concentration in the compartment.

In some cases, other gases may be present, both toxic and explosive.
Therefore it may be necessary to use a portable instrument that measures several gases at the same time.

Before stepping into, for example, a tank you should check the oxygen concentration in the tank with a portable gas detector.

Underground

In tunnels, such as sewers and other underground facilities the oxygen concentration may drop for various reasons.
In addition, other, both explosive and toxic gases may have been formed as a result of biological reactions.

For example, Methane (CH4), Hydrogen Sulfide (H2S), Carbon Monoxide (CO).

An combustion engine underground may consume the oxygen and leave carbon monoxide behind.

Leakage of different gases that are lighter or heavier than air, may lead to accumulation in different cavities.
When someone enters into such a cavity without first checking gas concentrations with an instrument it may lead to immediate death.

Sensor placement for monitoring oxygen

In cases where you want to monitor oxygen concentration in a room,

It is important to bear in mind which gas that could displace the oxygen.

Examples of gases that can displace oxygen, thereby causing suffocation are the inert gases,
such as Nitrogen (N), argon, helium, carbon dioxide, used in various industrial processes, hospitals, etc.

Important to mention here is that the fact that the carbon dioxide in addition to displacing the oxygen is also toxic itself.

If there is leakage of, for example, krypton, which has a higher density than air and will sink, the oxygen detector should be placed low.
If a gas with lower density than air, such as helium, should leak, the oxygen sensor should be placed high.

If the oxygen in a room risks being consumed by any form of combustion, the oxygen concentration will be reduced across the room which
means that the sensor placement here is not as critical as in the above examples.

High concentrations of oxygen

If the oxygen concentration in the air increases, the risk of fire dramatically increases.
All combustible products will be much more flammable.

Alarm limit is set at 23% O2.

Inhalation of high oxygen concentrations over time can be harmful.

Ventilation Control Products Sweden AB - Phone: +46-31-811666 - E-mail: info@vcp.se - Web: www.vcp.se
 Oxygen (O2) Gas Detector RO2 025 September 2021

Technical data
Calibration Oxygen O2

Sensor type Electrochemical cell

Sampling method Diffusion

Detection range 0-25% vol.

Overgas limit 30% vol O2

Resolution 0.01 % vol O2

Non-linearaty < 0.2% vol O2

Signal update every second

Response time
T90 15 seconds

Maintenance
interval 6 months

Sensor lifetime > 2 years

Self-diagnostics Full functionality check at start-up

Warm-up time ≤ 1 min

Power supply 11-30 Vdc

24 Vac as option

Power
consumption < 2 VA

Digital interface RS485, Modbus RTU protocol

Analog outputs 2 × 4-20 mA / 0-10 V, user settable

Enclosure Light-grey ABS plastic,

Protection class IP65 for both enclosure and sensor

The microporous PTFE dust filter ensure
IP65 also for the sensor.

Dimensions:
Enclosure H82 × W80 × D55 mm excluding cable gland
Duct probe L 230 mm x diameter 35 mm (only duct type)

Remote sensor
probe Protection IP65,
shielded cable default cable length
3 meters or 10 meters

Operating
environment Industrial indoor and outdoor areas
without aggressive gases

Operating
conditions -30 to +50 °C, 15 to 90 %RH
non ATEX rated areas
CE marking 2014/30/EU, EMC Electromagnetic Compatibility
2014/35/EU, Low Voltage Electric Equipment

Ventilation Control Products Sweden AB - Phone: +46-31-811666 - E-mail: info@vcp.se - Web: www.vcp.se
 Oxygen (O2) Gas Detector RO2 025 September 2021

The detector have been calibrated by manufacturer with standard gas mixtures before delivery.
Provided that the sensor is used under moderate conditions, field recalibration is recommended every 6 months.

Maintenance
Do not perform any maintenance operation with the power on.
Clean the device with soft damp cloth.
Do not use any abrasive cleaning agents.
Do not immerse the device into water or any cleaning media.

Delivery set
- Detector (wall mount or duct mount version)
- Mounting accessories:
4 screws with plastic dowels for wall mount version rubber flange for duct mount version. fixing clamp for remote probe version

The detector are supplied either in duct-mount or wall-mount version.

The wall mount version of the device is available with remote probe.
The remote probe is connected to the main unit with shielded cable.
Default connection cable length is 3 m.
The detector provides two independent analog outputs OUT1 and OUT2,
user selectable to 4-20 mA or 0-10 Vdc, proportional either to gas concentration or temperature.
RS485 Modbus RTU digital communication interface allows easy instrument configuration and integration into various automation systems.
A design with LCD is available as an option.

Safety requirements
Always adhere to the safety provisions applicable in the country of use.
Do not perform any maintenance operation with the power on.
Do not let water or foreign objects inside the device.

Operating conditions
The device should be used in explosion-safe (non ATEX -rated) indoor areas,
Without aggressive gases in the atmosphere.

Installation and connections

There are no precise rules or standards to follow when installing the gas detectors.
The following points must be taken into account:

application (air quality control or leakage detection),

properties of the space under investigation (room geometry, direction and velocity of air flows etc),

detected gas (relative density to air, whether the gas is flammable, or toxiс, or oxygen displacing),
safety: strong vibrations, mechanical shock, and the sources of strong electromagnetic interference should be avoided,

the device should be accessible for maintenance and repair.

For early leakage detection install the sensor as close as possible to the potential leakage sources
(flanges, valves, pressure reducers, pumps, etc), taking into consideration other points listed above.
For general area monitoring without definite leakage sources, the detectors should be distributed evenly in the room.
For personal safety control the detectors are installed in the breathing zone (at the height of the head of people or animals).
Recommended sensor position is vertical, pointing downwards.
See Installation guidelines section on the next page for more information.

Ventilation Control Products Sweden AB - Phone: +46-31-811666 - E-mail: info@vcp.se - Web: www.vcp.se
 Oxygen (O2) Gas Detector RO2 025 September 2021

Wall mount version:

Fix the device on a wall by screws, using cross-shaped mounting lugs supplied with the instrument
(see dimensional drawing below).

Duct mount version:

Cut hole with a diameter of 36-45 mm in the air duct at the chosen mounting place.
Place the rubber flange aligning the holes in the flange and the air-duct and fix the flange with four self-tapping screws.
Pass the sensor probe through the flange and adjust it to the appropriate depth.

Unscrew four lid screws and detach the lid from the transmitter.
Use two M16 cable glands to pass the cables of the power supply and of the external devices.
Plug the power cable and connect the analog outputs and/or digital interface terminals to the relevant devices according
to the connection diagram.

The screw less quick connect spring terminals on the Detector devices are
suitable for a wide range of wires with cross-section 0,2...1,5 mm2.

We recommend to strip the wire end by 8...9 mm and tin it, or to use the wire end sleeves.
To connect the wire, insert the wire end into terminal hole.
To disconnect, push the spring loaded terminal lever, pull the wire out, and release the lever.

Use twisted pair cable, e.g. LiYY TP 2×2×0,5 mm2 or CAT 5, to connect the device to RS485 network.
Use one pair for A and B wires and the second pair for common 0 V and power +U wires to connect the transmitter to Fieldbus network.
Respect polarity.
Overall length of all connections via RS485 interface should not exceed 1200 m.
The type of each analog output can be independently changed between 4- 20 mA and 0-10 Vdc with jumpers J1 (OUT1) and J2 (OUT2).
With closed jumper the output is 0-10 V, with open jumper the output is 4-20 mA.
By default both outputs OUT1 and OUT2 are assigned to gas concentration.
The device has built-in temperature sensor which may be tied to any of the outputs.
The output assignments and scales can be changed by Modbus commands.

NOTE If you use a version with LCD, only OUT1 is available.

Turn on the power.

The sensor heating up may take up to five minutes after switching on.
During this period relays, analog outputs and Modbus interface are off.
A LED placed on the PCB of the device allows to control the connection process.
The LED response to different processes is presented in the table below.

Make sure that the transmitter is properly fixed, the external devices connected, power on and control LED is constantly lit.
Place the lid back and fix it with the screws.
The device is ready to use.
It is recommended to keep the device on constantly, except for periods of maintenance and calibration, replacement etc.

Ventilation Control Products Sweden AB - Phone: +46-31-811666 - E-mail: info@vcp.se - Web: www.vcp.se
 Oxygen (O2) Gas Detector RO2 025 September 2021

Sensor probe handling

The wall mount version of the Detector is available with remote probe
The remote probe is connected to the main unit with shielded cable.
Default connection cable length is 3 m.
The sensor probes of all types are equipped with a hydrophobic microporous PTFE filter
to protect the sensor from dust, dirt and water drops.
The filter may be replaced if it gets strongly contaminated.
To replace the PTFE filter, unscrew the M25 nut and remove the old filter.
Place a new filter into the nut and tighten it again.

Dimensions remote sensor probe (option)

Note:
Protection IP65, shielded cable cable lenght 3 meters (RSP3) and 10 meters RSP10

NB! Never stab or press the filter near its centre where the sensor is located since this may damage the sensor.

The recommended orientation of sensor probe is vertical with the sensor tip pointing downwards.
This prevents possible accumulation of condensed water on the sensor protection filter.
The horizontal orientation is also suitable.
Avoid upward position of the sensor tip.

Ventilation Control Products Sweden AB - Phone: +46-31-811666 - E-mail: info@vcp.se - Web: www.vcp.se
 Oxygen (O2) Gas Detector RO2 025 September 2021

Configuring
The Detector features and options include:

- digital output change rate limiting filter

- digital integrating (averaging) filter
- temperature measurement channel with internal sensor
- free assignment of each analog output to chosen parameter
- flexible setting of analog output scales for each output
- output shift and slope adjustment for calibration
- Modbus controlled forced state option for analog outputs .

The detector can be configured through its RS485 interface by Modbus RTU commands.
A standard configuration kit includes Model E1087 USB-EIA485 converter and a software pack.
Please contact your Seller for more information.

Return to default settings

To reset the device’s Slave ID, baudrate and sbit number to factory settings, proceed as follows:
1. De-energize the device
2. Connect the J3 jumper
3. Turn on the device
4. De-energize the device
5. Disconnect the J3 jumper
6. Turn on the device

RS485 communication interface

See next pages

Ventilation Control Products Sweden AB - Phone: +46-31-811666 - E-mail: info@vcp.se - Web: www.vcp.se
 Oxygen (O2) Gas Detector RO2 025 September 2021

Electrical connection

Note:
For LCD version only OUT1 is available
 Oxygen (O2) Gas Detector RO2 025 September 2021

Dimensions in mm

Duct mount version

We reserve the right to make changes in our products without any notice which may effect the accuracy of the information contained in this leaflet.

Ventilation Control Products Sweden AB - Phone: +46-31-811666 - E-mail: info@vcp.se - Web: www.vcp.se
 Oxygen (O2) Gas Detector RO2 025 September 2021

Modbus RTU Communication Reference

* - The new value is applied after restart.

** - Broadcast slave ID 0 can be used to assign a new ID to device with unknown ID.
When addressing by ID 0 the device shall be the only Modbus instrument in the network.
The device will not respond to Master command when addressed by ID 0.

*** - This value is dynamic and not kept in EEPROM after restart

Ventilation Control Products Sweden AB - Phone: +46-31-811666 - E-mail: info@vcp.se - Web: www.vcp.se
 Oxygen (O2) Gas Detector RO2 025 September 2021

Modbus holding registers (part 2)

Register addresses are shown 0-based, Addr in hexadecimal, Reg in decimal format.
Modbus holding register numbers MHR are shown in decimal 1-based format, and may be addressed either from 00001 or 40001 base.

*- The new value is applied after restart.

** - Broadcast slave ID 0 can be used to assign a new ID to device with unknown ID. When addressing by ID 0 the device shall be the
only Modbus instrument in the network. The device will not respond to Master command when addressed by ID 0.

*** - This value is dynamic and not kept in EEPROM after restart

We reserve the right to make changes in our products without any notice which may effect the accuracy of the information contained in this leaflet.

Ventilation Control Products Sweden AB - Phone: +46-31-811666 - E-mail: info@vcp.se - Web: www.vcp.se