SEIKOM ELECTRONIC RLSW7 Flow Monitoring Water and Air Instruction Manual

SEIKOM ELECTRONIC RLSW7 Flow Monitoring Water and Air Instruction Manual

General Information

The flow in fluids can be monitored reliably with the flow sensor RLSW7. The sensitivity may be changed with a coarse (rough) and fine potentiometer. The switching state is indicated by an LED. In this device sensor and monitor are a compact unit. The probe’s pipe is also used for mounting. The advantages are the application where a switch-gear or other technical equipment has to be mounted in a small room or where no room is planed for example additional mounting.

Measuring principal

A temperature-sensitive resistor is heated according to the calorimetric measuring principle. The temperature sensitive resistor is heated by a second resistor. A flow dissipates heat from the measuring resistor, causing the resistor’s temperature to fall and thus a change of impedance. This temperature change is evaluated. Since both the velocity and the temperature of the flowing medium affect the dissipated heat, a relationship must be created between flow and temperature. For this purpose, a second temperature- sensitive resistor is located next to the first one. The second measuring resistor is not heated and is only used for the temperature measurement.

Airflow > / = switch point| Switching output is energised| Yellow LED “Airflow“ switch on
---|---|---
Airflow < switch point| Switching output isn’t energised| Yellow LED “Airflow“ switch off

Technical Data

CE, Type examination TÜV Nord DIN EN 61010-1:2011-07
Accessory| –| **** –

The device has two potentiometer for switching point adjustment, the upper is used for fine adjustment, and the lower for coarse adjustment

The glycol part in the media may not be bigger than 30%! Or else malfunctions and malmeasuring is possible!

Attention!

Connection and commissioning must be performed by properly authorized and qualified personnel!
Connections to mains supply (L, N) must be made by means of a protected isolating switch with usual fuses. As a matter of principle, the General VDE regulations must be complied with (VDE 0100, VDE 0113, VDE 0160). If the potential-free contact is connected to an extra-low safety voltage, sufficient insulation must be provided for the connecting cables up to the terminal, since otherwise the double insulation to the mains voltage side may be impaired. The current load capacity of the potential-free contact is limited to 6A.
Therefore, the electrical circuit of the potential-free contact must be protected by a 6.3A fuse

Installation Conditions RLSW7

To avoid malfunctions, the following points should be observed:

• The sensor needs to be installed in area where it is surrounded completely by the medium.
• Do not install directly behind bends (distance approx. 10x bend radius).
• Install the probe in the middle of the duct where possible (distance at least 1/3 of the duct diameter from the wall).
• Do not install directly behind heating register (rapid changes in temperature may lead to the measured values being falsified).
• Do not use a stainless steel sensor in a copper or brass tube! Through the use of chlorine or copper/brass tube pitting corrosion occurs. A stainless steel sensor should not be used here.

Cleaning
The airflow-sensor contains a sensor element which is very sensitive to mechanical loading and which must not be touched with hard and pointed objects. Any cleaning that may be necessary is possible in water (also with addition of detergents). Let the unit drip off and dry renewed start-up

Electrical connection

Dimension

(normal length of sensor: 46mm)

Setting the switch point

The relationship between air velocity and resistance change is non linear. In the lower flow velocity range the resistance change is very large. In the upper flow velocity range identical changes in flow velocity result in increasingly smaller resistance changes. When the switch point is set, it is important to note what change is to be monitored because different settings have certain disadvantages.
Be aware of the following requirements:

Small flow change in high flow velocity range: The switch point must be selected very close to the normal flow reading since flow changes only lead to a very small change in the measured value. Since temperature compensation takes place with certain delay after the actual temperature change has occurred, this switch point setting is only suitable for the applications which have slow temperature changes in the medium.

Small flow change in low flow velocity range: The switch point can be selected at a greater interval from the normal flow reading because a change in flow velocity causes a very large change in the measured value. A temperature change has not effect on switching behaviour.

Large change in flow rate: A Yes/NO statement is usually required here (e. g. fan running or fan stationary). You can therefore selected a safety clearance which is so large that neither temperature changes nor turbulence can have an affect on switching behaviour.

Comissioning

To avoid malfunctions the following points must be observed:

• The flow monitor must be installed according to the installing conditions.
• Set both potentiometers to lowest sensitivity (left limit stop).
• Switch on mains voltage; green LED “Voltage” enlightens, switch on work flow.
• Turn potentiometer „Rough“ slowly clockwise, until LED „Flow“ enlightens.
• After 2-3minutes, adjust the setting with potentiometer „Fine“. To achieve a stable switching point, you may turn potentiometer “Fine” slightly past the switching point.
• Check glycol concentration (max. 30%).

Trouble Shooting

Check mains voltage and connection
RLSW.. does not detect flow| Sensor installed incorrectglycol concentration bigger than 30%| Check installation conditionsreduce glycol concentration
RLSW.. exhibits changed tripping behavior| Sensor heavily contaminated by the mediumglycol concentration bigger than 30%| Carefully clean sensor with water reduce glycol concentration
RLSW.. switches at rapid temperature increase of the medium| Temperature gradient is outside of technical specifications| Turn potentiometer „Sensitivity“ slightly further clockwise. Check temperaturegradient of the system.

Mistakes and misprints are not to be excluded. All information „without guarantee“.

• SEIKOM-Electronic GmbH & Co. KG
• Fortunastr.20
• D-42489 Wülfrath
• Telefon: +49(0) 20 58/20 44
• Fax: +49(0) 20 58 / 79 111
• E-Mail: info@seikom-electronic.com 
• Internet: http://www.seikom-electronic.de

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