Setting The Configuration Switches - Thermo Scientific APEX 100 User Manual

Setting the Configuration Switches

To configure your Modbus card as an RS-485 termination node, do the following.
1) Locate the termination, node ID/baud rate, and parity switches (diagrammed below)
on the Modbus card. Set all the switches to the zero or "off" position. This allows the
APEX software to set all of the communication parameters for your RS-485 card.
2) Please check that DIP-switch number 5 in the parity block is set to the zero or "off"
position (as diagrammed below), because this is the switch that actually sets the
Modbus card to the RS-485 configuration. (If this switch is on, the card will be
configured as an RS-232 card.)
3) To configure the Modbus card as an end node in your network, set the termination
switch to the one (1) or "on" position (as diagrammed below).
When the termination switch is on, the Modbus' internal termination resistor network
is activated, which eliminates reflections on the bus line.
Configuring a Non-Terminated Node
To configure the Modbus card as a non-terminated node, or when using an external
terminator, set the termination switch to the zero or "off" position.
Page 346 Thermo Scientific APEX User's Guide