Rockwell Automation 1400-SP PowerMonitor Software - Manual (Page 18)

Chapter 3
Installation
3–4
!
ATTENTION: Never connect an RS–232C equipped
device to the DATA+ or DATA– lines of an RS–485
equipped communication system. Doing so will damage
the RS–485 driver circuits of every device within the site.
!
ATTENTION: Converters such as the Catalog Number
1400–CC converter must always be used between devices
that use RS232C/RS–485 communications standards.
If the computer running the Powermonitor Software uses an RS–232C serial
port in conjunction with an external Catalog Number 1400–CC RS–232C to
RS–485 converter, then install a straight 25–conductor RS–232C cable or a
cable configured with (3) wires to pins 2, 3, and 7 from the desired serial port
at the back of the computer to the RS–232C input on a Catalog Number
1400–CC converter. The DATA+ and DATA– lines on the RS–485 side of
the converter are then connected to the DATA+ and DATA– on each
Powermonitor via a shielded two–wire twisted pair cable as shown in
Figure 3.2.
Important: Be sure to connect both ends of the shield between devices.
Figure 3.2
RS–485 Communications Connections – External Converter
RS–232C
Port
IBM PC (DTE)
+
–
– + –
RS–232C
External RS–232C to
RS–485 Converter
SHIELD
SHLD To other
devices
Bulletin 1400–CC SHIELD
SHIELD
150Ω
Resistor
25 Pin
Male
Connector
(DB 25)
25 Pin
Female
Connector
(DB 25)
+ –
SHLD
Power–
monitor
#1
Power–
monitor
#2
Power–
monitor
#3
150Ω
Resistor
+ SHLD SHLD