Ashu@automation

Analog module in Siemens convert voltage (or other) into integer 16-bit (word data type), so it have 2^16 = 65536 count. Analog module in Siemens comes with varies bit-resolution 8-15 . So for max count (15 bit) it have 2^15=32768 count (0...32767).  PLC always convert voltage (or other) into word value regardless the resolution and its conversion is shown below:   Volt:    0....10         into Count: 0.....27648 although the rated range is 0-10V (0-27648), PLC also have over-control range (27649-32511), and overflow (32767). Noted that 27648 is not analog maximum value, its the analog rated maximum value. The real maximum value is 32767 (overflow) -> 2^15. So if you give module's input 10.2V it will convert into value bigger than 27648 and not destruct the module (as long as it still below permissible input voltage). But i still don't know why Siemens choose 27648 not 27000 or other (maybe rated range 84...

DIFFERENCE BETWEEN THERMOCOUPLE AND RTD The most notable difference between a thermocouple and an RTD (Resistance Temperature Detector) is the principle of operation.   A thermocouple operates on the principle that two dissimilar metals joined together will produce a voltage related to a temperature difference. An RTD operates on the principle that electrical resistance of certain metals changes in a predictable way depending on the rise or fall in temperature. Advantages of the thermocouple include a wide temperature measuring range (depending on the thermocouple type the range can be as much as from -300°F to 2300°F), fast response time (under a second in some cases), low initial cost, and durability. Overall, thermocouples are able to withstand rugged applications.    Advantages for RTDs include stable output over a long period of time, ease of recalibration, and accurate readings over narrow temperature spans. Disadvantages, when compared...