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Position feedback for greenhouse

Position feedback for greenhouse

EP PositioningUnit

The EP PositioningUnit (RPU) will help you to optimize your greenhouse climate. This advanced position sensor accurately monitors and relays the positions of air vents or climate screens, enhancing your control over the ambient climate. This will result in higher crop yields and less power consumption – boosting your profits, as well as benefiting the environment.

Your benefits at a glance:
• Flawless position monitoring
• Continuous reliability
• High return on investment
• Extremely easy to install
• Maintenance-free design

While in the past simply opening and closing air vents or screens would usually be sufficient, the introduction of the climate computer has led to much more sophisticated climate control. This requires continual adjustments to be made based on the weather conditions. The RPU is the new standard in position monitoring, serving as the crucial link between your climate computer and your drive system. Better position monitoring allows the climate to be controlled more precisely, increasing your crop yields and thus raising your profits.

Reliable and accurate position feedback

The RPU is a contact-free, multi-turn magnetic encoder equipped with a chip with integrated Hall sensors, which ensures a linear signal. The system is extremely accurate, continuously measuring with a resolution of more than 4000 positions per revolution. The RPU converts the digital signal into an analogue 4-20mA output signal. Above the sensor, there is a rotating non-wearing magnetic axis, mounted to the threaded limit switch shaft of the RW motor gearbox. The RPU uses a separate 24V power supply. If installed in a RLL300, the RPU can be connected directly to the power supply.

RPU versus potentiometer

The RPU has more benefits. For instance, you no longer have to recalibrate and correct the feedback signal every year, as was necessary with conventional potentiometers. Potentiometers also contain parts subject to wear and tear, leading to measurement deviations over time. RPU´s contact-free measuring technology is impervious to wear. This ensures that the quality of the feedback signal won´t degrade. The RPU can be installed in new and existingEP RW motor gearboxes with potentiometers.

Precision in practice

The measuring range can be perfectly aligned with the operating range of a ventilation or screen system. In practice, this means that an RPU is able to measure air vent positions with an accuracy of 0.5 mm and climate screen positions with an accuracy of 2.0 mm. The RPU can also set the measuring range smaller than a system´s operating range.

Reliable operation

The RPU monitors constantly whether the measuring signal is valid. If the measured value deviates from the expected value, it will generate an error message and send out a 0 mA signal. This may occur, for example, during a temporary interruption of the RPU´s supply voltage. If the RPU is connected to the limit switch system of the RW motor gearbox, this error message will be reset automatically when an end position is reached.

Fast return on investment

The RPU is a relatively small investment that will help you to optimize your greenhouse climate. The unit will be quickly pay for itself by allowing your climate computer to operate more effectively and reducing your energy consumption. Compared to the potentiometer that is subject to wear and requires frequent replacement, the RPU will provide significant savings in maintenance and replacement costs. 

Positioning Unit RPU for greenhouse

The RPU EP PositioningUnit is a high-accuracy digital positioning meter for use in inEP RW motor gearboxes, making it the perfect solution for obtaining accurate positioning data for ventilation, protection and lifting systems. The current position is monitored continually by the RPU and the position is fed back to a climate regulator using a 4-20 mA signal. The RPU can be used with all types ofEP RW motor gearboxes that are fitted with aEP RSU end switch system. The RPU can be supplied individually or built into an RW motor gearbox.

The 4-20 mA signal from the RPU is generated using a Hall sensor built into the RPU and a magnetic axis mounted above it. The magnetic axis rotates contact-free and is mounted on the limit switch shaft of the RSU end switch system in aEP RW motor gearbox. This contact-free measuring technology means that the RPU’s feedback signal value always remains constant and that the RPU requires no maintenance. During operation, the RPU measures the position continuously with a high degree of accuracy - 0.04% of the measuring range that has been taught in. From this measuring signal, the RPU calculates the 4-20 mA signal that needs to be fed back. This signal is reversible. Using an ohmic resistor, a 0-5 V or 0-10 V feedback signal can also be generated. The RPU is equipped with an operating button and LEDs so that its status can be read easily.

The RPU is easy to install and teach in. Normally, the measuring range to be taught in will correspond to the switching range of the RSU end switch system. The end positions taught in for the measuring range of the RPU (SP1 and SP2) will then correspond to the end positions of the RSU (ES11 and ES12). It is also possible to set one of the end positions for the RPU’s measuring range as an end position for the end switch system. The RPU’s measuring range will then be smaller than the switching range of the RSU end switch system. This is one solution for systems with a switching range that is larger than the measuring range of the RPU that is being monitored (between SP1 and SP2). This option also makes it possible to teach in RPUs with an identical measuring range for independently driven systems with different switching ranges for the end switch system (in order to position winchable feeding lines at the same height, for example).

While in operation, the quality of the signal is monitored constantly by an integrated reference monitor. If there is an external disruption, such as a loss of power, the value measured by the RPU will deviate from the expected value and the RPU will generate an error message as a result. A 0 mA value will then be fed back and a blink code will be displayed.

In order to carry out a reset after a reference deviation, the RPU is equipped with a reference input. The reference input can be connected to a duty switch in the RSU end switch system. By operating this duty switch in an end position, the reference deviation and the error message that it has generated will reset automatically. However, the switch position of this duty switch must correspond to the end position of the measuring range taught into the RPU.

The RPU PositioningUnit can also be installed and taught in in such a way that in the event of a reference deviation, the reference reset will occur through range recognition. The RPU can do this without a duty switch being connected to the reference input. However, in this case the entire measuring range taught in will then have to be travelled through to carry out the reference reset.

Art. no. Description [m]
502687 RPU 24V\4-20mA\V3\SET 0,1
Hongtai Liu Road, Xiaoshan District

Hangzhou City


Mon to Fri 9am to 6 pm

[email protected]

Send us your query anytime!

Potentiometer installation sets for greenhouse

TheEP potentiometer installation set, including potentiometer, is built into a EP RW motor gearbox and enables all the positions of the driven system to be fed back accurately. The potentiometer installation set allows you to easily fit and install a potentiometer in all EP RW45, RW240/400/ 600/800, RW200, RW1000/1400 and W1200S/ 1600S/ 2000S motor gearboxes.

The installation set includes a complete set of gear wheels with 14, 15, 18, 20, 24, 25 (2x), 30, 32, 36 and 40 teeth for optimum use of the potentiometer measuring range (90% of the maximum number of turns of the potentiometer). The gear wheels allow various transmission ratios between the potentiometer and drive shaft of the RW motor gearbox to be achieved and optimum use to be made of the potentiometer´s measuring range.

The potentiometer installation set comes with a potentiometer. Separate installation sets are available for the various turn ranges and resistance values of the potentiometer. The desired potentiometer depends on the required number of turns and the type of control that is being used. The potentiometer installation set is supplied as a complete set.

Art. no. Description [m] [R] rev
kg Ω
502653 POT-MET-SET RW\R500\S05 0,2 500 5
502654 POT-MET-SET RW\R01K\S05 0,2 1000 5
502655 POT-MET-SET RW\R05K\S05 0,2 5000 5
502656 POT-MET-SETRW\R10K\S05 0,2 10000 5
502657 POT-MET-SET RW\R500\S10 0,2 500 10
502658 POT-MET-SET RW\R01K\S10 0,2 1000 10
502659 POT-MET-SET RW\R05K\S10 0,2 5000 10
502660 POT-MET-SET RW\R10K\S10 0,2 10000 10
Hongtai Liu Road, Xiaoshan District

Hangzhou City


Mon to Fri 9am to 6 pm

[email protected]

Send us your query anytime!