RS-485¶
RS-485 expansion modules can be installed into the three (A, B, C) expansion slots for industrial I/O modules. This interface is implemented using the MAX13488 (or compatible) transceiver and interfaces with the processor’s UART ports. Up to three RS-485 modules can be installed simultaneously.
Configuration and access¶
Once properly installed into an I/O slot, the RS-485 interface can be accessed via the ttyRS485_X TTY device, where X is the slot name (A, B, C).
The controller also features optional software-controlled 120Ω termination resistors. The termination resistor is disabled after each power cycle. To change the termination state:
SLOT |
ENABLE TERMINATION |
DISABLE TERMINATION |
|---|---|---|
A |
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B |
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C |
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