ProSoft Technology PLX31-EIP-SIE - Manual (Page 156)

ASCII Protocol PLX3x Series
User Manual Ethernet and Serial Gateways
Page 156 of 218 ProSoft Technology, Inc.
September 17, 2014
8.1.3 Modes of Operation
The gateway can operate in several different modes with each port acting
in
dependently. The configuration of each port’s driver determines its mode. The
following topics describe these modes and describe the flow of data between the
pieces of hardware (ASCII device and PLX3x Gateway). These topics describe
the three possible types of communication devices that can be attached to
application ports: receive-only, transmit-only, and transmit-receive mode.
Receive-Only Mode
A port on the gateway configured to function in receive-only mode is set up to
only receive data from some sort of ASCII device. In this mode, the PLX3x
gateway will never transmit data back to the ASCII device. Any data received
from the ASCII device is passed from the receiver driver (Rx Driver) to the PLX3x
Gateway
’s internal database (Rx Data). The following illustration shows the flow
of data on a port configured for receive-only mode.
Configuring a Port for Receive-Only Mode
In order to set a port for Receive-Only mode, ensure that the Rx DB Start
parameter in the configuration file contains the starting location of where the data
will be stored. The Tx DB Start parameter must contain a value of -1. This value
indicates that the port will not transmit any data.