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As additional feature, the controller is
also provided with two pins (5V and 0V)
in order to apply the Fail Safe Open Line
protection method. To avoid erroneous
readings in Open-Line conditions, pull-
up and pull-down resistors should be
connected as shown.
The Fail-Safe resistors are connected only to one unit in
the line, and their value depends on the application and
characteristic impedance of the connection cable.
The RS485 port is optoisolated from measuring circuit and
power line. If both analog output and RS485 port are pres-
ent, they have the same ground.
RS485 PROTOCOL
The commands sent to the controller must have the fol-
lowing format:
• 2-digit process ID number
• 3-character command name
• Parameters (variable length, may be null)
• End of command (always the CR character, Hex
0D)
A maximum time interval of 20 ms is allowed between two
consecutive characters of a command.
It is possible to send commands to change the controller
settings or to simply ask information on the controller status.
Following is the complete list of commands available:
