Operating instructions

VLT
®
2800, VLT
®
6000 HVAC and VLT
®
8000 AQUA Modbus RTU
■ VLT 6000 Parameter Settings for Modbus
Communication
Using the Modbus RTU Protocol requires setting
of the below listed parameters.
See the VLT 6000 Operating Instructions
MG.61.AX.YY for details on selecting and changing
parameter values, if necessary.
500 Protocol
(PROTOCOL)
Value:
✭FC protocol (FC PROTOCOL)
[0]
Metasys N2 (METASYS N2)
[1]
Landis/Staefa Apogee FLN (LS FLN)
[2]
Modbus RTU (MODBUS RTU)
[3]
Function:
There is a choice of four different protocols.
Description of choice:
Select the required control word protocol.
501 Address
(ADDRESS)
Value:
Parameter 500 Protocol = FC protocol [0]
0 - 126
✭ 1
Parameter 500 Protocol = Metasys N2 [1]
1 - 255
✭ 1
Parameter 500 Protocol = LS FLN [2]
0-98
✭ 1
Parameter 500 Protocol = MODBUS RTU [3]
1 - 247
✭ 1
Function:
In this parameter it is possible to allocate an
address in a serial communication network to
each frequency converter.
Description of choice:
The individual frequency converter must be
given a unique address.
If the number of units connected (frequency
converters + master) exceeds 31, an amplifier
(repeater) must be used. Parameter 501 Address
cannot be chosen via serial communication, but
must be set via the LCP control unit.
570 Modbus parity and message framing
(M.BUS PAR./FRAME)
Value:
(EVEN/1 STOPBIT)
[0]
(ODD/1 STOPBIT)
[1]
✭ (NO PARITY/1 STOPBIT)
[2]
(NO PARITY/2 STOPBIT)
[3]
Function:
This parameter sets up the drive’sModbusRTU
interface to communicate properly with the master
controller. The parity (EVEN, ODD, or NO PARITY) must
be set to match the setting of the master controller.
Description of choice:
Select the parity that matches the setting for the
Modbus master controller. Even or odd parity is
sometimes used to allow a transmitted word to be
checked for errors. Because Modbus RTU uses
the more efficient CRC (Cyclic Redundancy Check)
method of checking for errors, parity checking is
seldom used in Modbus RTU networks.
571 Modbus communications timeout
(M.BUS COM.TIME.)
Value:
10 ms - 2000 ms
✭ 100 ms
Function:
This parameter determines the maximum amount
of time that the drive’sModbusRTUwillwait
between characters that are sent by the master
controller. When this amount of time expires, the
drive’s Modbus RTU interface will assume that it
has received the entire message.
Description of choice:
Generally, the value of 100 ms is sufficient for Modbus
RTU networks, although some Modbus RTU networks
may operate on a time-out value as short as 35 ms.
If this value is set too short, the drive’sModbusRTU
interface may miss a part of the message. Since the
CRC check will not be valid, the drive will ignore the
message. The resulting retransmissions of messages
will slow communications on the network.
If this value is set too long, the drive will wait longer
than necessary to determine that the message is
completed. This will delay the drive’s response to the
message and possibly cause the master controller to
time out. The resulting retransmissions of messages
will slow communications on the network.
✭ = factory setting. () = display text [] = value for use in communication via serial communication port
MG.10.S2.02 - VLT is a registered Danfoss trademark
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