Frequency Converter Parameter Settings For Modbus Communication; Fc Protocol Overview - Danfoss VLT DriveMotor FCP 106 Programming Manual

RS-485 Installation and Set...
1
3 3
1 DIP switch
2 DIP switch set to factory setting, OFF position
3 DIP switch ON position
Illustration 3.4 DIP Switch set to Factory Setting
3.1.4 Frequency Converter Parameter
Settings for Modbus Communication
Define the RS-485 Communication Set-up
Parameter
8-30 Protocol
parameter 8-31 Ad
dress
parameter 8-32 Ba
ud Rate
parameter 8-33 Par
ity / Stop Bits
parameter 8-35 Mi
nimum Response
Delay
18
®
VLT
3
Function
Select the application protocol to run on
the RS-485 interface
Set the node address.
NOTICE
The address range depends on the
protocol selected in 8-30 Protocol
Set the baud rate.
NOTICE
The default baud rate depends on the
protocol selected in 8-30 Protocol
Set the parity and number of stop bits.
NOTICE
The default selection depends on the
protocol selected in 8-30 Protocol
Specify a minimum delay time between
receiving a request and transmitting a
response. This function is for overcoming
modem turnaround delays.
DriveMotor FCP 106 and FCM 106 Programming Guide
Parameter
parameter 8-36 Ma
ximum Response
Delay
8-37 Maximum
Inter-char delay
2
Table 3.2 Modbus Communication Parameter Settings

3.2 FC Protocol Overview

The FC protocol, also referred to as FC bus or Standard
bus, is the Danfoss standard fieldbus. It defines an access
technique according to the master-follower principle for
communications via a serial bus.
One master and a maximum of 126 followers can be
connected to the bus. The master selects the individual
followers via an address character in the telegram. A
follower itself can never transmit without first being
requested to do so, and direct message transfer between
the individual followers is not possible. Communications
occur in the half-duplex mode.
The master function cannot be transferred to another node
(single-master system).
The physical layer is RS-485, thus utilising the RS-485 port
built into the frequency converter. The FC protocol
supports different telegram formats:
•
A short format of 8 bytes for process data
•
A long format of 16 bytes that also includes a
parameter channel
•
A format used for texts
3.2.1 FC with Modbus RTU
The FC protocol provides access to the control word and
bus reference of the frequency converter.
The control word allows the Modbus master to control
several important functions of the frequency converter.
•
Start
•
Stop of the frequency converter in various ways:
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MG03N102 - Rev. 2013-12-02
Function
Specify a maximum delay time between
transmitting a request and receiving a
response.
If transmission is interrupted, specify a
maximum delay time between two received
bytes to ensure time-out.
NOTICE
The default selection depends on the
protocol selected in 8-30 Protocol
Coast stop
Quick stop
DC Brake stop
Normal (ramp) stop