•
•
•
•
•
•
•
Run at various preset speeds.
Run in reverse.
Change of the active set-up.
Control of the 2 relays built into the drive.
The bus reference is commonly used for speed control. It is also possible to access the parameters, read their values, and where
possible, write values to them. Accessing the parameters offers a range of control options, including controlling the setpoint of the
drive when its internal PI controller is used.
8.3 Network Configuration
To enable the FC protocol for the drive, set the following parameters.
Table 51: Parameters to Enable the Protocol
Parameter
Setting
Parameter 8-30 Protocol
FC
Parameter 8-31 Address
1–126
Parameter 8-32 Baud Rate
2400–115200
Parameter 8-33 Parity/Stop Bits
Even parity, 1 stop bit (default)
8.4 FC Protocol Message Framing Structure
8.4.1 Content of a Character (byte)
Each character transferred begins with a start bit. Then 8 data bits are transferred, corresponding to a byte. Each character is secured
via a parity bit. This bit is set at 1 when it reaches parity. Parity is when there are an equal number of 1s in the 8 data bits and the
parity bit in total. A stop bit completes a character, consisting of 11 bits in all.
Start
bit
Even
parity
Stop
bit
0
1
2
3
4
5
6
7
e
9
5
n
a
0
3
6
.1
0
Illustration 67: Content of a Character
8.4.2 Telegram Structure
Each telegram has the following structure:
Start character (STX) = 02 hex.
A byte denoting the telegram length (LGE).
A byte denoting the drive address (ADR).
Several data bytes (variable, depending on the type of telegram) follow.
A data control byte (BCC) completes the telegram.
ST X
L GE
ADR
D AT A
BC C
e9
5n
a0
99
.1
0
Illustration 68: Telegram Structure
8.4.3 Telegram Length (LGE)
The telegram length is the number of data bytes plus the address byte ADR and the data control byte BCC.
Table 52: Length of Telegrams
4 data bytes
LGE=4+1+1=6 bytes
AJ363928382091en-000101 / 130R0983 | 105
Danfoss A/S © 2021.04
RS485 Installation and Set-up
VLT® Flow Drive FC 111
Design Guide
