WAGO-I/O-SYSTEM 750 XTR
Function Description 41
750-652/040-000 Serial Interface RS-232/RS-485 XTR
Manual
Version 1.3.0
5.1.4
RS-485 Operating Mode
The RS-485 operating mode in half-duplex is realized in a 2-wire multi-endpoint
(bus) connection. Simultaneous transmission and receiving is not possible with
2-wire connections. The I/O module switches to receive mode after transmitting the
content of the input buffer to the serial interface completely.
The “RS-485 switching time” parameter can be used to configure the time frame
when the I/O module should switch after transmitting the last character can be
configured.
Possible settings are:
•
100 µs (default setting)
•
Duration of the transfer of two characters with the current configuration
•
Duration of the transfer of four characters at the current configuration
5.1.5
RS-422 Operating Mode
The RS-422 operating mode in full-duplex is realized in a 4-wire point-to-point
connection. Simultaneous transmission and receiving is thus possible.
In this mode, the I/O module supports flow control for the serial interface using the
XON/XOFF protocol (see section “Flow Control Using XON-/XOFF Protocol”).
5.1.6
DMX Operating Mode
In DMX mode, the I/O module can both send and receive (firmware version 06 or
higher) data packets.
5.1.6.1 Sending Data Packets in DMX Mode
In DMX mode, the I/O module can operate as a DMX sender. In this case, up to 32
DMX receivers can be connected. The I/O module can also operate as a DMX
receiver with firmware version 06 or higher.
The transmission channel is based on RS-485 physics with a transmission rate of
250 kBaud, as well as 1 start and 2 stop bits. In this mode, no further settings are
possible.
The I/O module can transmit up to 255 bytes of data in this mode.
The I/O module can even send up to 513 bytes of data with firmware version 06 or
higher. In a DMX telegram, 1 channel occupies 1 byte.
Every transmission of a DMX telegram begins with the transmission of the DMX
start byte. DMX channels 1 to 254 can be operated, and DMX channels 1 to 512
with firmware version 06 or higher.
The possible refresh rate of DMX data depends on:
•
The number of channels being used
•
The performance of the fieldbus coupler
•
The number of I/O modules in the node