Allen-Bradley Rockwell Automation 857 User Manual page 208

7-2
Communications
Communication Ports (cont.)
857-UM001A-EN-P – July 2009
NOTE: When the programming cable is inserted to the front panel
connector, it activates the front panel port and disables the rear panel
local port by connecting the DTR pin 6 and DSR pin 4 together. See
Figure 7.1.
Protocol for the Local Port
The front panel port is always using the command line protocol for
SetPointPS regardless of the selected protocol for the rear panel local
port.
If other than "None" protocol is selected for the rear panel local port,
the front panel connector, when activated, is still using the plain
command line interface with the original speed, parity etc. For
example, if the rear panel local port is used for remote SetPointPS
communication using SPA-bus default 9600/7E1, it is possible to
temporarily connect a PC with SetPointPS to the front panel
connector with the default 38400/8N1. While the front panel
connector is in use, the rear panel local port is disabled. The
communication parameter display on the local display will show the
active parameter values for the local port.
Physical Interface
The physical interface of this port is RS-232, but the connector type
depends on the option module type.
Table 7.1 – Local Port Parameters
Parameter Value
Protocol
None
SpaBus
ProfibusDP
ModbusSla
ModbusTCPs
IEC-103
ExternalIO
DNP3
Msg# 0 ... 2 32 –1
Errors 0 ... 2 16 –1
Tout 0 ... 216–1
Unit Description
Protocol selection for the rear panel
local port.
Command line interface for SetPointPS
SPA-bus (slave)
Profibus DB (slave)
Modbus RTU slave
Modbus TCP slave
IEC-60870-5-103 (slave)
Modbus RTU master for external
I/O-modules
DNP 3.0
Message counter since the device
has restarted or since last clearing
Protocol errors since the device has
restarted or since last clearing
Timeout errors since the device has
restarted or since last clearing
Note
Set
Clr
Clr
Clr