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Any time I find I need to add input line filtering, I would much rather provide it by adding the simple RC hardware components rather than to complicate the software. The control cabinet for this machine is already overstuffed with components that we physically can't fit a CP341 unit in there! To the RF purist it's a shameful tradeoff, to an industrial control practitioner it's quite a no-brainer. This is extremely heavy filtering and probably more than needed for even the most severe situations. For example, if your requirement does not demand a fast response time for reading inputs, and you desire heavy filtering, I would suggest using the 100Ω resistor with the 10 or 22µF capacitor. For example, using QuickBASIC with my Pentium in data acquisition, I read input bytes 200,000 times per second. This works well for most applications, and is how the original input cards (the CIN24 cards using the 8255) function. Because none of the other SMINI cards were addressed, their corresponding U7’s are held in their high impedance tri-state, effectively open circuited, to prevent conflict with the operation of the addressed SMINI. Including the pull-up resistor is mandatory for the current-sourcing case to insure that the base voltage of the transistor is pulled sufficiently high when the latch is high so that the transistor is turned fully off.

Including the diode provides an ultra fast reset to minimize the wait time required when cycling power. This insures correct reset operation when power is cycled to the SMINI. Solar Power Systems: Solar power systems use RS-485 for communication between solar inverters, charge controllers, and monitoring devices. These AC to DC enclosed switching power supplies in MORNSUN SMPS Power Supplies portfolio meet IEC/EN61000-4, CISPR32/EN55032, IEC/UL/EN62368, EN60335, and GB4943 standards and are widely used in areas of industrial, LED, street light control, electricity, security, telecommunications, smart home, etc. They comply with the latest global energy efficiency standards. Battery safety sensors, such as the battery aerosol sensor (BAS) and battery pressure sensor (BPS) from Honeywell, provide early detection of thermal runaway in Li-ion battery packs of electric vehicles (EVs) and energy storage systems (ESS). Also on the TTI stand will be gas sensor technologies from SGX Sensortech. By substituting a 2N4403 PNP transistor and changing card jumper locations it is also possible to obtain a current-sourcing output configuration which I will cover in the next section. Circuit designers will be quick to observe that RN12 is not really required because the high output of the latch would turn on Q1 independent of having RN12.

With current-sinking, having the latch high turns on the load while with current-sourcing having the latch high turns off the load. When the output of the latch goes low the base of the 2N4403 transistor falls below the emitter, causing the transistor to conduct to activate the load. The 2N4403 PNP transistor provides a drive capability of .3A. Larger capacitors make these high-level currents present for longer time-periods exacerbating the drive requirement. Simply cut the narrower circuit trace located on the bottom side of the card under each of the resistor locations, and install the corresponding R6-R29 resistors and C24-C47 capacitors. Then later, if you find it desirable to add filtering, it is a simple task to cut the trace on the bottom side of the board and insert the desired parts. The Laureate interface board P/N L485 with dual RJ11 jacks allows multiple Laureate meters, counters, timers and remote displays to be daisy-chained to the same RS485 line and to be addressed in command mode.

In most higher level protocols, one of the nodes is defined as a master which sends queries or commands over the RS485 bus. Offering several advantages over Hall-Effect technology, the Bourns SSD digital smart shunt sensors feature a 16-bit automotive-grade microcontroller, a 24-bit ADC with buffered analogue inputs, plus flash memory with error correction code (ECC) capabilities. They want to run over CAT-5 (Ethernet) cable so they can use existing wiring. Adding a noise filter to each input line can reduce the effects of this noise. If you are interested in such fast tracking of inputs, and you installed the filter time constant of 47ms, it would take about 9,400 samples before you detect an input change, a totally unacceptable situation when seeking high speed data acquisition. Check out these isolated transceiver modules with a reasonable price along with high performance and we hope that they are an ideal fit for your application needs.

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