Rockwell Automation 2706-P42_P43_P44_P72_P74_P92_P94 InView Marquee Message Display User Manual - Manual (Page 36)

Publication 2706-UM016D-EN-P - March 2006
1-28 Install InView Marquee Message Display
RS-485 Echo The RS-485 echo feature addresses the issue of increased network
traffic often caused by multiple node addresses and high consumption
of communication bandwidth. The display’s design enables users to
daisy-chain numerous InView displays off an InView P9x via the
RS-485 communication network.
In order to set the 2706-P92C display or the 2706-P94C display as a
Master, the echo dip switch must be enabled.
See Dip Switch Information for the 2706-P9x in Chapter 2.
When the echo feature is enabled, all incoming packets, whether it is
over the RS-232 port, RJ12 download port, or the RJ45 10/100 base-T
Ethernet port, are echoed out the RS-485 port.
An InView master display inspects the incoming packets and
determine if the packet is addressed to itself and take the appropriate
action. The master shall ignore all packets that are not addressed to
itself. The only exception is for a packet with an address of 255. This
is the broadcast address and must be accepted by all displays on the
network.
2706-P9x - Master InView
RS-485 Network
TIP
Only one 2706-P9x InView display can be set as the
master per RS-485 network.
TIP
When the 2706-P9x display, echo feature is enabled,
the RS-485 port of the 2706-P9x display, does not
accept incoming packets. The port is exclusively
used to echo out data.