Hardware reference guide

CPU Modules
156
35013379 11/2011
Front Panel Switches
Two, three-position slide switches are located on the front of the CPU. The left
switch is used for memory protection when in the top position and no memory
protection in the middle and bottom positions. The three-position slide switch on the
right is used to select the comm parameter settings for the Modbus (RS-232) ports.
The following figure shows the three options that are available for the 140CPU43412
module.
NOTE: The CPU hardware defaults to bridge mode when the front panel switch is
set to RTU or ASCII mode. When networking controllers, a panel device connected
to the CPU Modbus port can communicate with the controller to which it is
connected, as well as log into any nodes on the Modbus Plus network.
Setting the slide switch to the top position assigns ASCII functionality to the port; the
following comm parameters are set and cannot be changed.
5 503 ram address test error
52D P.O.S.T BAD MPU ERROR
6 402 ram data test error
7 300 EXEC not loaded
301 EXEC Checksum
8 8001 Kernal prom checksum error
8002 flash prog / erase error
8003 unexpected executive return
LED Error Codes
Number of Blinks Code Error
ASCII Comm Port Parameters
Baud 2,400
Parity Even
Data Bits 7
Stop Bits 1
Device Address Rear panel rotary switch setting