Answer / akshetty11

hart give frequency signal (1200hz) to comunicate. 4-20ma is current signal

Answer / asif

This enables two-way field communication to take place and makes it possible for additional information beyond just the normal process variable to be communicated to/from a smart field instrument. The HART Protocol communicates at 1200 bps without interrupting the 4-20mA signal and allows a host application (master) to get two or more digital updates per second from a smart field device. As the digital FSK signal is phase continuous, there is no interference with the 4-20mA signal.

while stroke checking of a linear control valve ,found its travel is in non linear ,what can be possible reason ? ( please answer send in mannanali65@gmail.com) pls pls pls if any body know

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