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Original question:
Dear Luis, thank you
Please, see my previous thread and your answer.
Point is that, I do not need high measurement accuracy. Error 10-15% will suit me.
In fact, the signals, transmitted on this line, are pulsed signals with a duration of 10 ms. On the transmitting side, the signal has an amplitude of +/-12 V.
But due to the line length it can weaken up to +/-50 mV at the receiving side. On the receiving side I need to detect whether there is a pulse or not. Since there are noises in the line, the analysis is performed using the ADC (after PGA281). If the amplitude of the pulse at the receiving side is more than 500 mV, then there are no problems at all - even the ADC can be omitted (I can use a comparator). But if the amplitude is less than 500 mV, then against the background of noise it is already more difficult to analyze.
Honestly, I don’t know if the common-mode voltage will be more than +/-15V. Actually shouldn't be. But with lightning discharges, everything is possible. Gas arrester and suppressor do not always help. That's why I expect to "increase" the protection of MUX507 with resistors R3/R4. Аnd I would like to know what size I can choose them: 1 kOhm,10 kOhm or 100 kOhm ? It may not be very good, but putting INA148 at the input of each line is expensive.
We used DG408DY multiplexers earlier. In principle, everything worked, although sometimes there were failures. Are they any better, than MUX507? (in terms of surge protection). Please, see attach.
TIA
Vladimir Naumenkov
www.agat.by
