HOHNER AUTOMAZIONE SRL Mechanical connections.

The path followed by electrostatic discharge is not always immediately foreseeable (it behaves a little like a bolt of lightning) but using few precautions it can be re-routed to areas where the risk of danger is less. The following suggestion should be taken into consideration: - If we assume that a system is made up of quality components or components which have been selected on the basis of certain criteria, we can state that the more efficient the measurement system, the more precisely the system behaves. The more precise and accurate the assembly, and the more detailed the control of the parts, the more efficient the system. From the mechanical point of view the encoder must never be subject to stress, as is requested on the other hand of every measuring instrument (whether it be protruding, hollow or semi-hollow) must be connected to the drive shaft of the apparatus which requires measuring using couplings or elastic joints suitable for the specific case to reduce as far as possible axial and radial errors between the shafts themselves. Since the consist of precision moving parts, the encoder cannot be subjected to high loads: the part would deteriorate resulting in reduced life on the one hand and risk of losing precise readings on the other. The encoder must be located so as to avoid: high temperature fluctuations, exposition to liquids or neutral or aggressive oils, knocks; it should not be used as a support and also the shaft must never be modified (punctured, milled, cut, etc.) so as not to compromise connections with ensure that the grounding system is in correct working order; - use all metals industrial encoders rather than plastic ones; - use high quality shielded wire and connect the shield to both ends; - avoid isolating mechanical joints to the flange of the encoder and if this not possible, use very thick materials with extremely high dielectric strength. The metals joints and fixtures must be rust-proof; - carry out frequent checks to see if the components responsible for discharging materials and equipment, which due to their very nature, concentrate electrostatic energy are in good working order; - in certain cases in order to protect the encoder electrically it is necessary to fit discharges (zenamic or varistors, section industrial filters etc) to all the signals and supply points. The connections of the protections must be located between the encoder and a good earthing point. b earings and irreversible damage of the optic disk which is often made from glass.

Electrical disturbance

In a measurement a disturbance is considered to be any signal other than the signal which we wish to interpret. It is obvious that we need, first of all, to avoid the occurrence of such phenomena and furthermore equip the measuring system in such a way that we don’t falsify the measurement and/or damage the instruments themselves.

Electric/electronic connections.

Once you have defined the disturbance and ensured that the information transmitted by the encoder to the central

Electrostatic charges and discharges

p rocessing unit is always comprehensible, it than becomes necessary to know the nature and intensity of disturbances generated by other apparatus so that we can size the most suitable system of communication and choose the best When evaluating where to put the encoder in environments where there may be accumulations of powerful electric charges (for example in areas where synthetic materials are handled) it becomes of vital importance for the encoder that all the routes of dispersion, i.e. earthing system of all metallic structures, are examined and made very precisely. The presence of an electrostatic discharge p erforming interface. Once the means and the system of communication have been chosen it is than necessary to separate the signal line of the encoder from power and system lines (if this is not possible metal channels with separate compartments must be used), always select the shortest route, avoid stretching and/or squeezing wires, fit filters (mains, interference filters etc.) and shield to all appliance and apparatus which are responsible for generating such disturbances. There are various methods for transmitting digital information. p assing through the encoder can, in all probability, destroy every electronic device. It must be remembered that energy irradiated during an electrostatic discharge can reach extremely high values (as high as tens of thousand of volts) and that the electric field generated can link up to circuits and electric cables a considerable distance away.
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