BeiJer X2 base 7, Quick Start Manual

 
X2 Control communication with BFI-E3 by Modbus TCP 

SER0020_V1.0.0  2020-11

29 (31)

Nor

m

a

l.d

o

tm

, 

2

0

2

0

-07

-01

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  

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 (P-12 <>3 or 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.  

Exception Code 2: Invalid Modbus register  

Returned under the following conditions  

-

Network Master attempts to read or write a register that does not exist within the drive.  

Exception Code 3: Register Value Out of Range  

Returned under the following conditions  

-

Network Master attempts to write a holding register with a value outside the range of the register  

Exception Code 6: Drive Busy  

Returned under the following conditions  

-

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  

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 P-12 = 3, P-15 =0 and digital input 1 is closed):  

      Request: [01]  

[06] 

 [00] [00] 

[00] [01] 

 [48] [0A]  

    (Drive Addr)  (Command)  

(Reg addr)  

(Data value) 

(Checksum)  

 
      Reply:    [01]  

 [06] 

[00] [00] 

 [00] [01] 

 [48] [0A]  

    (Drive Addr)  (Command)  

(Reg addr)  

 (Data value) 

 (Checksum)  

     Note: The actual address of register 1 on the data link is 0. All data in [ ] is in 8bits Hex format.  

Reply can be error message depending on drive parameter settings and digital input status.