Hach-Lange SC 200 Modbus Module User Manual - Manual (Page 8)

Configure the network
D A N G E R
Electrocution Hazard. Always remove power from the instrument
before making any electrical connections.
The Modbus module provides an interface for either a RS485 network or
to an RS232 connection. Before use, the module must be configured for
the type of network. Use the switch settings on the back side of the
module for configuration (refer to the Installation section). Refer to
Table 2 for the network configuration.
Table 2 Modbus network configuration
Switch
number Switch ON (to the
right) Switch OFF (to the left) Function
1 RS485 network
terminated RS485 network un-
terminated RS485 network bus
termination
2 RS485 biasing RS485 no biasing RS485 network biasing
3 RS485 biasing RS485 no biasing RS485 network biasing
4 RS485 selected RS232 selected Select Modbus type
RS232 Modbus connection
Hold the module to look at switches 1, 2, 3, and 4 on the side. The green
wire connectors should point up.
1. Move switch 4 to the left (OFF position).
The RS232 Modbus connection is set.
RS485 Modbus connection
Hold the module to look at switches 1, 2, 3, and 4 on the side. The green
wire connectors should point up.
1. Move switch 4 to the right (ON position).
The RS485 Modbus connection is set.
2. A network bus termination is required for a proper and reliable
operation and when the Modbus module will be at the end of the
network wiring. Move switch number one to the right (ON position) to
terminate the bus.
3. Move switch 2 and 3 to the right (ON position) to enable biasing if
network biasing is not provided by another device on the network.
RS232 connection to 9-pin connector
Refer to Figure 1 for the RS232 connection to the customer-supplied
computer 9-pin D-subminiature connector.
Figure 1 9-pin female connector
1 Rx (2) 3 Ground (5)
2 Tx (3)
Operation
User navigation
Refer to the controller documentation for keypad description and
navigation information.
8 English