Type 2530H1
8
Figure 11. RS485 Installation Guidelines
100 OHM RESISTOR
A6798 / IL
Figure 12. M1000 Series RS232 to RS485
ConverterBack Panel
W6490/IL
the RS485 input. (The connection labeled RS485 IN is
only used when the unit is installed as a repeater.)
The set of ten switches near the center of the
back panel determine the converter baud rate.
The set of three switches near the RS485 OUT
connector determine the termination and biasing of the
RS485 output.
For the set of three switches adjacent to the RS485
connectors, when in the up position the switch labeled
1K places a 1k ohm pull-up resistor between the
DATA+ line and +5 Vdc. Placing the switch labeled
–1K in the up position connects a 1k ohm pull-down
resistor between the DATA– line and ground. Placing
the switch labeled 220 in the up position terminates
the RS485 input or output with a 220 ohm resistor.
For additional information on setting the converter DIP
switches, refer to the converter instruction manual.
Note
Do not use a pencil to set the switches.
Graphite from the pencil can fall into the
switches causing them to fail.
To set the switches, use a pointed object to push the
switch to the desired position.
Setting the Converter RS485 Termination
and Biasing
When the converter is used as an RS232-to-RS485
converter, set the three switches adjacent to the
RS485 IN connector as follows: set the switches la-
beled +1K and –1K to the up position and the switch
labeled 220 to the down position. When using the unit
as a repeater place all three switches in the up posi-
tion.
