User manual

gpio.Relais
with issues resulting of this, Modbus ASCII is the only available protocol used
over USB.
1
A gpio.NET card is detected as a virtual serial port by the host
system and so does not differ from a real one from a programs point of view.
USB device port is used as power source if connected to a host. As an
alternative, PIN9 from either X10 or X11 can used instead.
2
When using PIN9
care has to be taken to use a well-regulated 5 volts source.
RS232
A serial interface with RS232 levels is
available at gpio.NET module's X11 DSUB
connector. Except the both data lines and
GND no additional control lines are used.
3
The RS232 interface is capable of de- and
encoding Modbus-RTU as well as Modbus-
ASCII. The highest possible baud rate is
250k baud. By contemporaneous utilisation
of USB and RS323, it is possible to control
one additional card connected via RS232
using the hosts USB connection.
Pin X11
1
2 RXD
3 TXD
4
5 GND
6
7
8
9 VBUS
Table 1: Assignment
RS232
RS485
The R-Series offer possibility to link via a
RS485 bus. In that case, both potential
data lines are available on X10 as well as
on X11.
4
In this manner, a RS485 bus is
easily realised with RS232 cables. As if
using RS232, Modbus-RTU and Modbus-
ASCII are both usable. The maximum bit
rate is 1 Mbit. A 110 ohms terminating
resistor is selectable by jumper J4.
Table 2: Assignment RS485
Via RS485 connected cards are routed over USB to the host, allowing access to
the RS485 bus is without special PC hardware.
1 Modbus RTU – the standard mode – requires the exact temporal detection of a characters
reception. This criterion cannot be guaranteed on standard PCs what causes RTU mode to
become instable. Modbus ASCII is not affected by this constrain.
2 Ring indicators (PIN9) of both DSUB are connected with USB 5V power source (VBUS) (valid
for X10 only with connected jumper J7). This way, power can be transmitted to the next or
all gpio.NET modules in one RS485 bus system.
3 When plugging into a PC's RS232 interface, consider the RS485 assignment that is using
control lines of a standard RS232 interface. These pins (DTR, DSR) should not be connected
to a PC directly.
4 The potential data lines use standard RS232 control lines DTR and DSR. Connecting those
signals to a PC directly is to be avoided.
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Pin X10 X11
1
2
3
4 RS485+ RS485+
5 GND GND
6 RS485- RS485-
7
8
9 VBUS VBUS