LAFERT HP Combi Flow - Serial Communications

56 | HPI Combi Flow User Guide | Version 3.11 www.lafert.com
10. Serial Communications
10.1. RS-485 Communications
HP Combi Flow has an RJ45 connector located within the wiring enclosure of the drive. This connector allows the user to set up a
drive network via a wired connection. The connector contains two independent RS485 connections, one for Lafert Group’s Optibus
Protocol and one for Modbus RTU / BACnet MSTP. Both connections can be used simultaneously.
The electrical signal arrangement of the RJ45 connector is shown as follows:
1 Not used
2 Not used
3 0 Volts
4 -RS485 (PC)
5 +RS485 (PC)
6 +24 Volt
7 RS 485- Modbus RTU / BACnet MSTP
8 RS 485+ Modbus RTU / BACnet MSTP
Warning:
This is not an Ethernet connection. Do not connect
directly to an Ethernet port.
Warning:
When using Modbus RTU or BACnet, ensure that the
0V signal (T3) is also used to avoid comms errors
and potentially damaging common mode voltages.
   There are two RJ45 ports present in the IP66 outdoor rated drive. The two RJ45 ports are connected in parallel internally to help
support a network connection without the need for a splitter. Either port can be used.
  The Optibus data link is only used for connection of Lafert Group peripherals and inter-drive communication.
  The Modbus interface allows connection to a Modbus RTU network as described in section 10.2. Modbus RTU Communications.
10.1.1. RS-485 Communications Electrical Connections
Modbus RTU/BACnet
RS485 Controller
RS485+
RS485-
0 Volt / Common
Ground
NOTES
• Use 3 or 4 Conductor Twisted Pair Cable
•RS485+ and RS485- must be twisted pair
• Ensure the network taps for the drive
are kept as short as possible
• Using Option OPT-2-BNTSP-IN is
preferred
•Terminate the network cable shield at
the controller only. Do not terminate at
the drive!
•0 Volt common must be connected
across all devices and to reference 0 Volt
terminal at the controller
•Do not connect the 0V Common of the
network to power ground
RS485+
RS485-
0 Volt / Common
Shield
OPT-2-BNTSP-IN
OPT-2-BNTSP-IN
12 3
RS485+ 0 Volt / Common
Connection to the
drive through the
option
OPT-2-BNTSP-IN
RS485-
Pin 3 –0 Volt / Common
Pin 7 – RS485- (Modbus RTU)
Pin 8 – RS485+ (Modbus RTU)
RJ45 connector pinout
Direct connection to the drive
through the built-in RJ45 port
1 2 3 4 5 6 7 8
1
2
3
4
5
6
7
8
10
Serial Communications