Serial Communications 83
Modbus Exception Response Telegrams
Under some circumstances, the drive may reply with an Exception Response (error)
in response to a request telegram sent from the network master, for example where
the master tries to read a register which does not exist. Exception Responses which
can be generated by the drive are listed below:
Exception Code 1: Invalid Request
Exception Code 1: Invalid Modbus register
Exception Code 1: Register Value Out of Range
Exception Code 1: Drive Busy
Exception codes may be returned under the following conditions:
• Network Master sends an unsupported Modbus command (e.g. Read Coils).
• Run command issued to drive whilst the drive is not set for Modbus Control Mode
(e.g. 1103 <>4).
• Run command issued to drives whilst the drive is not enabled (e.g. Digital Input 1
is open).
• Run command issued to drive whilst the drive is in a tripped condition.
• Network Master attempts to read or write a register that does not exist within the
drive.
• Network Master attempts to write a holding register with a value outside the range
of the register
• Drive busy due to internal data transfer. The Network Master should re-send the
message after a delay
Dataflow Example
Read data from register 6
Display Scaling Source
0:Motor Speed
1:Motor Current
2:Analog Input 2 Signal
3:PI Feedback
Display Scaling Factor : 3dp, e.g. 0 – 16000 = 0.000 – 16.000
Request:
[01]
[03]
[00] [05]
[00] [01]
[94] [0B]
(Drive Addr)
(Command)
(Reg start addr)
(No. of Registers)
(Checksum)
Reply:
[01]
[03]
[02]
[00] [00]
[B8] [44]
(Drive Addr)
(Command)
(No of data bytes) (Data)
(Checksum)
Note: The actual start address of register 6 is 5. All data in [ ] is in 8bits Hex format.
Write start command to the register 1 (suppose 1103 = 3, 9902 =0 and digital input 1 is closed):
Request:
[01]
[06]
[00] [00]
[00] [01]
[48] [0A]
(Drive Addr)
(Command)
(Reg addr)
(Data value)
(Checksum)
ACS260-04.book Page 83 Thursday, December 24, 2020 4:33 PM
Summary of Contents for ACS260-04 Series
Page 2: ...ACS260 04 book Page 2 Thursday December 24 2020 4 33 PM ...
Page 4: ...ACS260 04 book Page 4 Thursday December 24 2020 4 33 PM ...
Page 8: ...8 Table of contents ACS260 04 book Page 8 Thursday December 24 2020 4 33 PM ...
Page 14: ...14 Safety ACS260 04 book Page 14 Thursday December 24 2020 4 33 PM ...
Page 22: ...22 Mechanical installation ACS260 04 book Page 22 Thursday December 24 2020 4 33 PM ...
Page 32: ...32 Electrical installation ACS260 04 book Page 32 Thursday December 24 2020 4 33 PM ...
Page 92: ...92 Technical Data ACS260 04 book Page 92 Thursday December 24 2020 4 33 PM ...
Page 96: ...96 Options and Kits ACS260 04 book Page 96 Thursday December 24 2020 4 33 PM ...