Watlow PPC-2000 - Manual (Page 105)

PPC-2000 User’s Guide Chapter 2: Hardware Installation
Doc.# 30002-00 Rev 2.3 Watlow Anafaze 81
Connecting RS-232 Communications
RS-232 may be used for communications between one PPC and
a host device over cables of up to 50 feet in length.
RS-232 does not support more than two devices on a network.
See Figure 2.69. RS-232 may be used to connect a computer,
through a 232/485 converter, to an RS-485 communications
network with up to 32 PPC controllers. See Figure 2.70.
Figure 2.69 Connecting One PPC to a
Computer Using RS-232
Connecting RS-485 Communications
An RS-485 communications network can connect up to 32 PPCs
directly with a host device equipped with an RS-485 port or via
a converter to a host’s RS-232 port. See Figure 2.70. RS-485
wiring can be used over much greater distances than RS-232.
Figure 2.70 Connecting Multiple PPCs to a
Computer Using RS-485
RS-232 Cable
Serial Port
DB-9 or DB-25
RS-232 4-pin RJ-type
serial port
232 Communications
optically
isolating
232 to 485
converter
no more
than 10 ft.
PPC 1 PPC 2 PPC N
485
flat cable
with RJs
485 Communications
terminal
block
external
resistor
termination
shielded twisted pair cable