Would you be able to advise on using the AD5700 for protocols other than HART?
Does the AD5700 simply convert RS-232 to Bell 202 and vice versa, or does it
only respond to HART encoded data?
Just to clarify, although the AD5700 is marketed as a HART modem, it is not
limited to use on HART registered devices, and could be used for other
protocols that are based on the Bell 202 standard (1200Hz and 2200Hz) over
The AD5700 has a UART serial interface with logic levels as defined in the
datasheet (see "logic_levels.png"). If using RS-232, one would have to use
level-shifters to convert to the required interface levels. In terms of the
specifically HART encoded data, the AD5700 will accept any UART data @ 1200
baud rate and convert it into a HART output signal. However, having said this,
it would be recommended to send at least 1 preamble character at the start of
the message for synchronization purposes.
The AD5700 does not care about the contents of the message that is sent to the
UART, once it has a baud rate of 1200 and has voltage levels per the datasheet.
The caveat re the presence of a preamble for synchronization purposes still