With the development of electronic products, [b] electronic weighing [/ b] has been more widely used. At present, our company has more than 10 sets of [b] electronic weighing [/ b]. In its use, often there will be a wide range of abnormal phenomena, the quality of the equipment is a problem, because of interference caused by the abnormal ground and is also a problem that can not be ignored, may cause serious damage to the equipment: lightning damage electronic components , The ground caused by bad shows such as the value of the drift, which we need a fundamental analysis of up to resolve the interference problem.
　　First, the main [b] interference [/ b] and suppression
　 1, interfere with power: power [b] interference [/ b] tend to surge to the form, such as lightning or a power line into the induction charge. It caused broken fuses, printed circuit board damage, damage to bridge rectifier, and so on. A complete system on the ground interfere with the power to play a good role in the protection. A good grounding system, to reduce the losses brought about by the failure, the system on the ground that such failures can play an effective role to prevent.
　 2, AC interference: AC [b] interference [/ b] possible damage to components and microprocessor. On AC power, zero-voltage line between the earth and should not exceed 0  2V, the ground next to the pile on the ground. Such interference is the best way to a good ground and the use of filtering interference on the role of the regulator"s source.
　　3, sensor interference: induction [b] interference [/ b] by the inductive magnetic field generated by the destruction, in order to interfere with the tip of the high-voltage form of it than the original is much higher voltage, the tip can cause a variety of voltage Failure of equipment and cause permanent harm. It is mainly for the performance of the capacitive coupling, inductive coupling, electromagnetic radiation in the form of three, the main cause Mode circuit in the form of interference. Coupled electric field to overcome the interference is the most effective way to shield. Coupled interference shielding electric field, the shield wire is best not to connect the two ends of the local line, because there are places in the ring current, which will form a magnetic shield, interference by shielding the wire. Shield should be a single point of grounding, the general office of the choose which one end of the earth. Magnetic interference suppression is the source of interference shielding. However, they are composed of magnetic materials together shielding very difficult to achieve, can only use passive suppression technology, away from sources of interference, at the same time to minimize the risk of running-line.
　　4, radio frequency [b] interference [/ b]: radio frequency interference may be caused by electronic scales are not allowed to show, this time to check whether or not to use ground equipment and a long thin wire, the shield is a good line, whether or not the normal work of the filter .
　 5, static: static than the radio-frequency interference of the great destructive power. When the damp equipment, electrostatic interference would occur, and this interference of the more common. Static electricity may interfere with obvious damage [b] sensor [/ b] and the sensitive components, resulting in the closure of facilities, indicating confusion. To overcome this interference is the best way to ground equipment, shielding the signal line, and so on.
　　As can be seen from the curb all kinds of interference, the ground may be the best measures must be well grounded understanding of the technology. Refers to the so-called grounding electrical circuit or equipment and the earth, in place of or in connection with the earth wire connections between the conductor. Can play a role in grounding as follows: ①, the provision of equipment and objects near the inter-connected low-impedance, so as to reduce the personal risk of electric shock. ②, to the earth fault current to return power to provide low-impedance path, so that the fuse or circuit breaker to move. ③, to the lightning induced current to provide low-impedance on the path to discharge. ④, electrostatic charge to provide access to discharge to prevent or have a spark arc. One is the anti-grounding technology to avoid interference with the ring current, and the second is to reduce the public resistance of the ground-coupled interference.
　　 Second, the type of earth and the role of
　　 Electronic equipment "grounded" usually has two meanings: one is "The Good Earth" (safe); and the other is the "base system" (to signal); refers to the ground in the system and a potential base-level between Low resistance of the conductive path set up. "Then the earth" is based on the potential Earth-based, and as a land of zero potential to the metal electronic devices, circuit reference point and connected to the earth, earth as a result of a very large capacitor is generally believed that the earth potential of zero . Weak in the grounding system in general is not true sense of the earth and connected to the ground. The power electronic devices will be in direct ground on the land or take in a conductor"s potential as a reference, when a current through the reference to the potential, then place in the circuit is the common point of reference, this voltage is 0V , In other circuit voltage of the high and low points are based on this point. Grounding a variety of ways, we used to have the following:
　 1, grounding security: security is about to ground the case with high-pressure equipment to connect the earth. The first case to prevent the accumulation of charge, discharge static electricity and equipment and endanger their personal safety. If the computer"s chassis ground. Second, when the insulation damage to the equipment and charged case, the power to protect the movement and cut off power supply in order to protect the safety of staff. Third, the device can shield a huge electric field, played a role in the protection.
　 2, Lightning grounding: [b] electronic weighing [/ b] when it was struck by lightning, whether directly or induced lightning struck by lightning, in the absence of appropriate protection, equipment may damage or even scrapped. In order to prevent lightning strikes, we generally set up in height and a lightning rod connected to the earth in order to prevent lightning when endanger the safety of equipment and personnel.
　 3, grounding the work: it is normal for the circuit and work to provide a benchmark potential. The benchmark set to zero potential in general. The potential base can be set to a circuit system, a certain period, and so on. When the potential base is not connected with the earth, as the relative potential of zero. But the relative potential of zero is unstable, as it is outside of the electromagnetic field changes, the system parameters change, leading to instability in the circuit system. When the base of the potential to connect with the earth, earth as a potential base of zero potential, and with the outside world will not change the electromagnetic field.
　 4, when the introduction of ground lines in order to prevent interference should stay away from other grounding system, in particular the mine or the power network neutral earthing system. If the grounding line is very long, in order to prevent high-current sensors, it is necessary to avoid high-power electricity lines parallel to the stick tight or the laying, if necessary, to shield grounding line pipe wear.
　Fourth, grounding
　The grounding wire ligation in the scale of the foundation piles on the ground, the method and Copper equivalent, when the pit do a good job, and grounding wire connected to ground pile. In addition the use of ground pile ground, with [b] grounding wire [/ b] connection pile ground, as ground piles will be covered by concrete, when the pit following the completion of the grounding wire and a pile connected to ground, the surface is concrete, if Concrete in the internal wires, it will be affected by corrosion, null and void brought about by the connection, the concrete has not yet formed before the welding on steel from the ground pile, this approach is very effective.
　 In doing grounded, [b] weighing system [/ b] take the place of the distance between not less than 3 meters, the laying of vertical, vertical depth into the ground floor should not be less than 2 meters to 3 meters in general, the level of Lay, laid the depth of not less than 0  7 meters. Moreover, the grounding should be copper or zinc, the painting is strictly prohibited. Using cross-section of not less than 25 mm2 of copper, which is not less than l-ohm resistors. Earth to do a good job, the general grounding resistance is less than 4 ohm

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