Danfoss VLT AutomationDrive FC 300 Design Manual page 236

FC 300 Design Guide
Telegram timing
The communication speed between a master
and a slave depends on the baud rate. The
adjustable frequency drive's baud rate must be
the same as the master's baud rate (selected
in par. 8-32 FC Port Baud Rate).
After a response telegram from the slave, make sure there is a pause of at least 2 characters (22
bits) before the master sends a new telegram. At a baud rate of 9600 baud, make sure there is a
pause of at least 2.3 ms. When the master has completed the telegram, the slave's response time
to the master is maximum of 20 ms. There is a pause of at least 2 characters.
Pause time, min: 2 characters
•
Response time, min: 2 characters
•
Response time, max: 20 ms
•
The time between the individual characters in
a telegram may not exceed 2 characters, and
the telegram must be completed within 1.5 x
nominal telegram time. At a baud rate of 9600
baud and a telegram length of 16 bytes, the
telegram is completed after 27.5 ms.
Telegram length (LGE)
The telegram length is the number of data bytes plus the address byte ADR and the data control byte BCC.
The length of telegrams with 4 data bytes is: LGE = 4 + 1 + 1 = 6 bytes
The length of telegrams with 12 data bytes is: LGE = 12 + 1 + 1 = 14 bytes
The length of telegrams containing texts is 10+n bytes. 10 represents the fixed characters,
while the "n" is variable (depending on the length of the text).
Adjustable frequency drive address (ADR)
Two different address formats are used. The adjustable frequency drive's address range is either 1-31 or 1-126.
1. Address format 1-31
The byte for address range 1-31 has
the shown profile:
Bit 7 = 0 (address format 1-31 active)
Bit 6 is not used
Bit 5 = 1: Broadcast, address bits (0-4) are not used
Bit 5 = 0: No Broadcast
Bit 0-4 = Adjustable frequency drive address 1-31
default setting ( ) display text
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236
How to Program
[ ] value for use in communication via serial communication port
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