Configuration
OMG-USB-485-1
Page
6
Configuration
Electrical Interface Selection
The port on the
OMG-USB-485-1
has the ability to be used as RS-530/422/485,
RS-422 or 2 wire RS-485. This is selectable via the DIP-switch SW1. The chart
below describes each of the switch position’s function. Please refer to the
following page for switch setting examples. Switch SW1 ON enables, adds and
connects. SW1 position OFF disables, removes and disconnects.
SW1
Function
1
RS-485 Two Wire Auto Enable/Disable
2
Echo Enable/Disable
3
Adds or removes the 120 ohm termination
4
Adds or removes the 1K ohm pull-up resistor in the RS-422/RS -485
receiver circuit (Receive data only)
5
Adds or removes the 1K ohm pull-down resistor in the RS-422/RS -485
receiver circuit (Receive data only)
6
Connects the TX+ to RX+ for RS-485 two wire operation
7
Connects the TX- to RX- for RS-485 two wire operation
8
Not Used
