Plc programming should follow the following basic principles. 1) The contacts of external input and output relays, internal relays, timers, counters, etc. can be reused many times without complicated program structure to reduce the number of contacts used. 2) Each line of the ladder diagram starts from the left busbar, the coil is connected to the rightmost side, and the contact point cannot be placed on the right side of the coil, as shown below. 
3) The coil cannot be connected directly to the left bus. If necessary, it can be connected through a normally closed contact of an unused internal relay or a normally open contact of a special internal relay R9010 (normally 0N), as shown below. 
4) A coil of the same number is used twice in a program called a double coil output. Double coil output is easy to cause misoperation, and coil re-use should be avoided as much as possible. 5) The ladder program must conform to the principle of sequential execution, that is, from left to right and top to bottom. If the circuit that does not conform to the sequence execution cannot be directly programmed, for example, the bridge circuit shown in the figure below cannot be directly programmed. 
6) There are no restrictions on the number of connections in the ladder diagram and the number of times the joint is used. It can be used indefinitely, as shown in the figure below. 
7) Two or more coils can be output in parallel, as shown below: 
Optical filter is a kind of optical element that selectively selects the transmission, reflection, cut-off and attenuation of spectral wavelength. According to its function, it can be divided into band pass filter, long wave pass filter, short wave pass filter, two Color filters, neutral density filters (ND Filter), notch filters, cold mirrors, hot mirrors, color filters, etc. Divided into interference filters and color absorption filters. These filters are widely used in industries and product fields such as spectral analysis, biomedicine, machine vision, fluorescence microscopy, and industrial automation. The band-pass filter selectively allows certain spectral wavelengths to pass through and prevents certain spectral wavelengths from passing through in its spectral range; the neutral density filter (ND Filter) reduces the transmittance of the specified spectral wavelength range, thereby Reduce luminous flux, which is conducive to the protection of sensors/electronic components. It has a wide range of applications in the field of laser optics/optoelectronics; cold/hot mirrors can specifically reflect and transmit light with longer wavelengths in the spectral range, and are widely used Applied in the lighting system, it is helpful to remove the heat generated in the lighting system.
Beam Splitter Filter,Nawrrow Bandpass Filter,Longpass Filter,Shortpass Filter
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