5. USER INTERFACES
Figure 33: Typical connection of the 12-bit I/O port circuitry:
MODBUS ASCII Configuration and Address Space
The 12-bit I/O Port registers are read and written using MODBUS ASCII slave protocol
over serial port 1. Using this protocol, it is possible to configure the 12-bit I/O board, read the
input status, and control the output. The I/O port communicates at 9600 baud, 8 bits, no parity,
and 1 stop bit (8N1). MODBUS input/output address space in the table below:
Address
Access
Description
0x0000
R/-
Type of firmware
0x0001
R/-
Upper 16 bits of firmware version
0x0002
R/-
Lower 16 bits of firmware version
To be continued on the next page
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