Host Commands; Stand-Alone Operation; Host Operation - Allen-Bradley 2755-DS1A Product Data

Product Data
Bulletin 2755
Single/Dual-Head Enhanced Bar Code Decoders

Host Commands

Stand-alone Operation

Host Operation

28
The decoder also supports a set of host commands for configuring the
decoder, monitoring operations, and triggering the scanner. Host commands
are sent to the decoder from a PLC controller or computer and perform the
same functions as the configuration software.
The HOST port accepts commands using the RS-232, RS-422 or DH485
interface and supports a variety of communication protocols.
The decoder can operate as a stand-alone device or be connected to a host
device. As a stand-alone device, the decoder uses output modules to control
external devices. The decoder sends discrete output signals to external
control equipment based on the results of decoded data.
The discrete I/O can also be controlled remotely by host commands or
manually via the configuration screens.
The decoder can also communicate directly with a host computer, PLC or
SLC controller in a control or data collection application. The decoder
communicates with and transmits bar code data to a host computer or
controller via the HOST port of the decoder.
Programmable Logic Controllers (PLC)
The decoder connects to an Allen-Bradley PLC as follows (see Figure 5):
1. Flexible Interface Module (Catalog No. 2760-RB) which supports a:
– Point-to-Point link using the RS-232, RS-422, or DH485 interface
of the HOST port.
– Multi-drop link using the DH485 interface of the HOST port and
the Flexible Interface Module. Each port of the Module operates
as a separate network, supporting up to 31 decoders.
Use the Catalog No. 2760-SFC2 or -SFC3 protocol cartridge
with the Flexible Interface Module and configure the decoder
for DH485 mode.
2. Catalog No. 1771-DB BASIC Module or 1771-DA ASCII I/O Module
connects decoder directly to a PLC.