Sentek RT6, Hardware Manual

Page: 38 / 90

SENTEK
Page 34
Jumper settings The RS485 signal must be terminated at both ends of
the cable. The last logger is terminated by installing
the “TERM” jumper (JP1). All other loggers
connected to the cable must have their “TERM”
jumper removed.
Note un-terminated loggers can be removed without
effecting data communication between computer and
loggers. However the last terminated logger must not
be removed without leaving the cable terminated.
If the Main Board is to be removed for a period
during which data communication is to occur, either
put a 120 ohm resistor between Pin A and Pin B on
the RS485 cable-end connector or move the
terminator to the prior RT6 logger and unwire the
final cable from that logger.
Jumper JP2 (see Appendix E – Overlay Diagram) is
used to select either RS232 or RS485 external
communications. To enable RS485 connection the
“RS232/RS485” jumper should be in the “RS485”
position as marked.
Front
panel/remote
switch
RS232-RS485
converters
Also, the switch on the Front Panel should be set to
“Remote” position for communication through the
RS485 connection or to “Front Panel” for local
communication through front panel RS232 connector.
Various forms and makes of RS232-RS485
converters are available for computers which may be
purchased from local computer suppliers along with
appropriate twisted pair screened data cable.