Select termination for the module, Base module to expansion interface – Rockwell Automation 1791R-XXXX CompactBlock Distributed I/O on Remote I/O Series D I.I. User Manual
Page 19

CompactBlock Distributed I/O on Remote I/O Series D 19
Publication
1791R-IN002B-EN-P - August 2003
Select Termination for the Module
The terminator resistor is provided in the module. Use the DIP switches to
select termination for the module. See below.
Base Module to Expansion Interface
The base module is linked to the expansion module with an 8-bit parallel bus,
control lines, Vcc and ground connections, a reset/initialization line, and an
expansion presence line. The 8-bit bus is multiplexed so that 16 bits of data (1
for each I/O point) can be transmitted/received with two transfers. The
reset/initialization line is used during initialization of the module. The
presence line is used for the detection of an expansion module at power up
and for a period of each data transfer. Module ID is read over this bus at
power up.
1791R modules supply expansion power via expansion bus as follows:
Expansion power voltage
5Vdc
Expansion power current
100mA
Switch
SW1
SW2
ON
Terminator on *1
Terminator on **2
OFF
No Terminator
No Terminator
* 1 at baud rate 230.4KBPS.
**2 at baud rate 57.6KBPS or 115.2KBPS.
Line 1
SW1
82 ohm
Line 2
SW2
150 ohm
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