Connecting To A Cms; Modbus Rtu - Carrier 39HXC Manual

5 - CONNECTING TO A CMS

The controller may be connected to a local or remote supervision PC via most communication protocols (ModBus RTU, ModBus IP,
LonWorks, KNX or BACnet IP).
Using KNX, LonWorks, ModBus IP or BACnet IP requires the installation of optional boards. The Modbus/BACnet, KNX and LON
communication tables are available separately.
NOTE:
If using a communication bus, the routing and processing of the available data are outside of our scope of supply. They must be
provided by the installer, and require the involvement of an integrator.
Parameter P716 indicates whether buses BMS1 and BMS2 are operating in read only mode (local control) or read/write mode (remote
control).
149 Th Tune

5.1 - Modbus RTU

The controller has a RS485 port and can natively communicate via ModBus RTU. The controller is a ModBus slave on port J11-BMS2.
Parameters P710 to P716 are used to configure this port.
710 Selecting the communication protocol type used on the BMS2 port
711 Selection of the transmission speed on the BMS2 port
712 Parity on the BMS2 port
713 Number of stop bits on the BMS2 port
715 Selection of the controller address on the BMS2 bus
149 Control type
The cable must be a type AWG20/22/24 (Filotex FMA-2P, Belden ref. 9842 / 9842NH 24AWG or equivalent) shielded cable
(not supplied), comprising a twisted pair and shielding, and must be no longer than 1000 m. This network must never run parallel to
power cables at a distance of less than 50 cm. These cables may cross, but perpendicularly. You are requested not to form a loop with
the network cable or the earth braid, and to properly separate the various cable families (control, power, earth and communication
bus).
A 120 Ω ¼W electrical heater must be connected to the RS485 serial board, in the last position on the bus.
The data format (16 bits, signed or Boolean) is ModBus standard, except for analogue data which is in the format "Integer multiplied
by 10".
The codes for the ModBus functions used are:
- 1 or 2: Read several bits
- 3 or 4: Read several registers (16 bits)
- 5: Write one bit
- 6: Write one register (16 bits)
- 15: Write several bits
- 16: Write several registers (16 bits)
ModBus
0: local
1: Remote
1: ModBus RTU
0: 1200
1: 2400
2: 4800
3: 9600
4: 19200
0: without
1: odd
2: even
0: Local
1: Remote
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