מיני-טנסיומטר אנלוגי (מתאים לעציצים, מצע מנותק, קרקע רדודה)
Main uses: Long term continuous follow up of the changes in the humidity of the soil with no need to be physically present in the field. Seeing the data from anywhere and at any time using a variety of apparatuses, like a computer, smartphone, tablet, and the like. The possibility to activate irrigation automatically in accordance with the condition of the humidity of the soil. Of course, the options of the use depend also on the model and the manufacturer of the various control and monitoring systems in the market. The analogue tensiometer of Ami Tens sends a standard output (4-20 mA or 0-2 V).
מבנה המכשיר ועקרון הפעולה
The analogical tensiometer is made up of a plastic tube with a transparent part in its upper segment, whereas a porous ceramic dome is connected to its bottom end. Below the transparent little window is screwed in an analogic vacuum transducer, and on the uppermost end of the tube there is a cap that screws in in order to fill in water.
The analogical vacuum transducer: The body of the transducer is a cylinder of stainless steel having a length of 6 or 4 cm and a diameter of 2 cm which is screwed into the body of the tensiometer with a G ¼” thread. In order to fill in or add water it is necessary to remove the cap manually and to close it using force at the end of the procedure. The ceramic is inserted into the area of the roots whereas its outside is in close contact with the soil and its inside is in contact with the water in the tube. The dryer is the soil, the greater will be the tension of the water (sub-pressure) inside the tube and we read the data. The vacuum meter indicates the tension in units of negative pressure, that is, millibars (for light soil) in the following values: 0 -- for saturated soil, up to 250 -- for totally dry soil, or centibars (for heavy/medium soil) in the values: 0 -- for saturated soil, up to 100 -- for totally dry soil. After irrigating or rain, the tension of the water will decrease. By following up continuously the farmer can decide when and how much to irrigate in the most efficient manner.
Optional Technical Specification
All what you have to choose is the scope of the measurement of the transducer (0 to 100 centibars or 0 to 250 millibars) in accordance with the rate at which the substrate gets dry and the output voltage of the transducer in accordance with the irrigation controller that you are using. Additionally, the depth of the tensiometer in order for the ceramic at the bottom (the middle of the ceramic) to be at the uppermost level of roots of the plant or at the level of the middle of the roots or the bottom level of the roots. Since it is a mini-tensiometer meant for a little plant, it is possible to make do with one apparatus in order to obtain data that will allow making a decision regarding the timing and the amount of the irrigation. As a standard, we provide tensiometers at depths of 15 and 20 cm. The tubes are made of PVC with an outer diameter of 12 mm. The length indicated is not the physical length of the tube, but that of the tube that is appropriate for installing at the desired depth. We provide a label indicating the depth, whereas the label is at the level of the surface of the soil.
General Comments
- You have to read the directives regarding the location and the use of the data in the Chapter on tensiometers in general. It is important to point out that, when using an analogical tensiometer, great importance is attached to choosing a transductor that has an electrical output that is suitable for controlling the irrigation, which you will be using, (unless you acquire, in favor of the tensiometers, a dedicated controller that will be placed together with the tensiometers) in order to be able to interface with it and to document changes and tendencies that occur continuously in the soil. It is important to mark the tensiometer in a way that stands out and to protect it from getting broken accidentally.
- It is also possible to provide analogical tensiometers with different characteristics, such as: Scope of measurement 0-60 centibars, depths that are different from the standard and the like. In order to receive an offer for a product with a unique characteristic, you have to submit a request to the Company and we will make an offer accordingly.