Mettler Toledo IND780 Manual De Instalación página 65

Port connector assignments for this board are shown in Figure 2-60, and
termination for RS232, RS422 and RS485 in Table 2-7.
Table 2-7: Serial Option Board Pin Connections
Pin Signal
1 TxD
2 RxD
3 GND
4 TxD+ RS-422/485 Transmit +
5 TxD- RS-422/485 Transmit -
6 RxD+ RS-422/485 Receive +
7 RxD-
8 +5V
9 +12V
10 GND
Figure 2-60: Connector Terminations for Serial Option Board
RS-485 Transmission Line Termination
The RS-485 network should include a terminating resistor, installed between the
two lines at or on the last node. The terminating resistor should match the
characteristic impedance of the transmission line, approximately 120 ohms. This
terminating resistor is required when connecting ARM100 modules to the port.
Function
RS-232 Transmit data
RS-232 Receive data
RS-232 Signal ground
RS-422/485 Receive -
+5V out, 0.5 A max.
+12V out, 0.5 A max.
Ground
IND780 Installation Manual
Notes
Jumper to RxD+ for RS-485
Jumper to RxD- for RS-485
Jumper to TxD+ for RS-485
Jumper to TxD- for RS-485
2-37