Switch S401
Block diagram RS-485
The switch S401 is located in the
device on the main board.
Factory setting:
S
Function
Settings for RS-485
1
Rx bus termination
OFF: not connected
ON: (RxA 120
Ω
RxB)
2
Rx pull-up resistor
OFF: not connected
ON: (RxB 1K6
Ω
+V)
3
Rx pull-down resistor
OFF: not connected
ON: (RxB 1K6
Ω
-V)
4
Tx/Rx bus termination
OFF: not connected
ON: (TxA 120
Ω
TxB)
5
Change-over 2-/4 wire
OFF: 4-wire
ON: 2-wire
6
Rx enable (unblock)
OFF: Rx disabled (blocked);
if Tx enabled (unblock):
S7 must be "ON".
ON: Rx always enabled (unblocked):
For 4-wire S7 must be OFF.
7
Tx enable (unblock)/Rx disa-
ble (block) (2-wire)
OFF: S6 must be "ON".
ON: S6 must be "OFF".
8
n.c.
no function
Transmitter in field housing PR 5230
4 Device installation
Minebea Intec
EN-44