in reply to: Multidrop & Tag & ID posted by Marco Schramel on 24 October 2002 at 12:59:39.
In HART Universal Command Rev 5, you could not use analog current signaling in multidrop mode because the current loop was fixed. Multidrop mode was established by setting the device polling address from 1 to 15. The device was then required to fix its analog output current, typically to the lowest value, ie, 4mA. If you want analog current signaling, you must set the polling address to 0 (point-to-point). This is different in HART 6. Polling addresses are permitted from 1 to 63, and the host tell the device if it wants it to fix its output (disable signaling).