User Manual

Table Of Contents
Serial (RS232/USB) Operation
178 Advanced Digital Motor Controller User Manual V2.1 December 3, 2020
Extending the RS232 Cable
RS232 extension cables are available at most computer stores. However, you can easily
build one using a 9-pin DB9 male connector, a 9-pin DB9 female connector and any 3-con-
ductor cable. DO NOT USE COMMERCIAL 9-PIN TO 25-PIN CONVERTERS as these do
not match the 25-pin pinout of the controller. These components are available at any elec-
tronics distributor. A CAT5 network cable is recommended, and cable length may be up to
100’ (30m). Figure 14-3 shows the wiring diagram of the extension cable.
1
2
3
4
7
8
9
5
1
2
3
4
5
6
7
8
9
6
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:
TABLE 14-2. Connecting with TTL devices
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: