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ASCII Protocol PLX3x Series ♦ Multi-Protocol Gateways
User Manual
Page 140 of 215 ProSoft Technology, Inc.
January 25, 2018
Note: If you want to access module status data in the upper memory, you can use the data
mapping feature in the gateway to copy data from the module status data area to the user data
area. See Mapping Data in Module Memory (page 24). Otherwise, you can use the diagnostic
functions in ProSoft Configuration Builder to view module status data. For more information on the
module status data, see ASCII Diagnostics (page 147).
8.1.4 ASCII Modes of Operation
The PLX3x gateway can operate in several different modes with each port acting
independently. 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 (the ASCII device and the gateway). These topic describe the
three possible types of communication devices that can be attached to
application ports: receive-only, transmit-only, and transmit-receive mode. See
ASCII Configuration (page 142) for the specific configuration information for each
mode.
Receive-Only Mode
A port on the module configured to function in receive-only mode only receives
data from an ASCII device. In this mode, the gateway never transmits data back
to the ASCII device. Any data received from the ASCII device is passed from the
receiver driver (Rx Driver) to the gateway’s internal database (Rx Data). The
following illustration shows the flow of data on a port configured for receive-only
mode.