User Manual

Serial (RS232/USB) Operation
168 Advanced Digital Motor Controller User Manual V2.0 July 8, 2019
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TX Data
RX Data
Data Out
Data In
GNDGND
DB9 Female DB9 Male
FIGURE 14-3. RS232 extension cable/connector wiring diagram
Connecting to Arduino and other TTL Serial Microcomputers
Arduino and similar microcomputers have a TTL serial port. There are Roboteq controllers
supporting RS485, so the connection can be done directly. However, for the rest of the
controllers there is a full RS232 serial interface. RS232 has the following differences from
TTL serial:
RS232 TTL Serial
Voltage Levels +10V/-10V 0-3V
Logic level Inverted Non-Inverted
A TTL to RS232 adapter must be therefore be used to convert to the Arduino serial inter-
face. Newer Roboteq controller allows the RS232 signal to be non-inverted. Interfacing
to Arduino or other TTL Serial interface can therefore be done with just a resistors, and 2
optional diodes as shown in the diagram below:
FIGURE 14-4. Simplified TTL to RS232 connection