Installing The Modbus Rs-485 Cable - Advanced Energy AE 75TX Installation And Operation Manual

Advanced Energy
I
Communications Interface PCB
-----------------------------------+---------------------------------,
Shield
I
.
-
Shield
I
.
-
I I
00 0 00 0
0
------------- ------- ------- --------------- -------
\
c
RS-485
Network to Field
(Inverter or Gateway)
0
------ ------------
4660
/
Modbus slave
I
I
L RS-485
Network to Field
(Inverter or Gateway)
Figure 6-8. Connecting dual Modbus slave pott terminal blocks
Installing the Modbus RS-485 Cable
6-10
MODBUS RS-485 WIRING REQUIREMENTS
The Modbus RTU connections are made using shielded, insulated, 18-24 gauge
twisted-pair communication cable that has a characteristic impedance of 120
Q.
If
the
RS-485 network will not pass through any high voltage (> 300 V) areas, then 300 V
rated cable may be used in the low voltage data monitoling compartment of the
inve1ter. Check with your local inspector or project engineer if you need assistance in
detennining this requirement.
Some appropliate 300 V data cables include:
• Belden 3 105A (1P22 A WG shielded)
• Belden 3082A (1P 15 AWG
+
1P 18 AWG shielded)
Belden 7897A (1P 15 AWG
+
1P 18 AWG shielded) is an example ofa 600 V rated
cable that may also be used; others exist as well.
TO INSTALL THE MODBUS RS-485 CABLE
Lt
DANGER:
Risk of electrical shock. High voltages are present in the inverter cabinet.
Both AC and DC disconnects must be in the OFF position when working on
the unit. Wait five minutes to discharge high voltage before opening the front
panels of the inverter.
Data Monitoring and Controls 570-1001793-0SB