Preliminary manual AN 401 Plus V2 r12 25/10/12
-12 / 20-
2.14.2
RS485 and RS422 line terminator resistor
MULTI DROP connections, like RS485 and RS422, require having a resistance applied at both ends of the communication line
(if not yet present inside the connected devices); one is to be placed in parallel to the last AN401
plus
and one on the PLC or
computer on the other end.
AN401
plus
has no internal resistance for RS485 or RS422 but It can be applied under customer’s request.
This resistor has to be 120 Ohm ¼ Watt.
This resistance is to be applied solely on the last AN401
plus
of the serial net, in order not to lower, too much, the overall line
impedance (fig.11).
3
Instrument setup
3.1
How to set parameters
This chapter describes the sequence to be used to set AN401
plus
, as working parameters and It is valid for
all of Its different menus. All different operational modes share the same sequence to set the desired
values or parameters, or levels.
