TagMaster XT-1, Manual

Page: 16 / 32

XT-1/XT Mini Manual 13-111 05, 2015-08-14
Page 16 of 32
RS485
The RS485 interface can be used for communication with a host system.
Connections
RS485:TX+ Transmitted data to host
RS485:TX- Transmitted data to host
RS485:GND Signal ground #3
RS485:RX+
Received data from host
RS485:RX- Received data from host
Max cable length 1000 m
Wire size
The cable for the RS485 interface must be a twisted pair cable and
conform to the EIA RS485 standard.
Max Baud Rate 115.2 kb/s (default)
Table 10 RS485 connection overview
The hardware supports 2-wire (DIP S301:1-2 ON) and 4-wire communication, half duplex and full duplex as
well as multi-drop. When using RS485 communication, correct termination of the interface should be
considered in order to handle transmission-line effects.
The XT-1 has a built-in option (DIP S301:3 ON) of
120
Ω
termination on the receive side (to be used at each end of the RS485 chain), and an option
(DIP S301:4-5 ON) of 620
Ω
bias on the receive side (to be used at one node in the RS485 chain). The
options using DIP switches are detailed in Figure 15 and also described in section 3.13.
With factory default settings, the reader should always be configured in 4-wire mode (DIP S301:1-2 OFF)
since the TAGP protocol requires a full-duplex link. Other protocols require different settings.
Figure 15 RS485 DIP switch configuration
The default output of the RS485 interface is tag data in ASCII format. If SecureMarkID
®
tags from
TagMaster are being used (recommended) the numeric identity is sent out. If other EPC tags are being
used the default output is the EPC data. The data is followed by CR+LF ("\r\n").
A TAGP connection can be initiated by sending the HELOTAGP message to the reader. The TAGP
connection is terminated with the QUIT message. Other protocols can be enabled using the web interface.
These protocols are described in separate manuals.
All RS485 settings are available under Settings…/Interfaces…/RS485 in the web interface.
RS485
driver
RX+
RX-
TX-
TX+
S301:1 S301:2
S301:5
S301:3
S301:4
5V iso
120 Ω
620 Ω
620 Ω