Setting Up; Termination Resistors - ABB 4620 User Manual

5 SETTING UP

For all aspects other than serial data transmission the
transmitter is set up as shown in the Operating Instructions
– see Section 1. Unless otherwise requested, the instrument is
despatched with a transmission rate of 9600 baud and
transmission line termination resistors linked-out. If the
resistors are to be linked-in (see Fig. 5.1) carry out the
following section.
5.1 Termination Resistors – Fig. 5.1
For long transmission lines, termination resistors are required
on the last 4600 Transmitter in the chain and at the host
computer/computer terminal.
conditions the resistors are required at the last 4600 receive
inputs only – see Fig. 4.1. The transmitter's resistors are
selected using plug-in links – see Fig. 5.1.
Switch off the supply and gain access to the processor board
(Section 4 in the Operating Instructions). Set the termination
resistor links as shown in Fig. 5.1.
Under normal operating
Processor Board
IC22
IC24
Termination Termination
Resistors Resistors
IN OUT
Fig. 5.1 Termination Resistor Links
IC23
IC25
5