CX-Protocol

[Derickvdw 0]

Hello All I need to help with CX-Protocol. I uploaded a Protocol file from a CJ1 which controls a string of 3G3MV inverter. Because we can't get the MV we ned to give the client a solution of another drive. V1000 preferably. But I first want to under stand the Protocol send to the drive from CX Protocol The string below is a complete string that is in the Send message DATA area. Is there any body that can tell me what each bit means please <a>+DLE+[0002]+[0001]+STX+(R(2),2)+<c> 3G3MV.zip

[Jay Anthony 118]

The string <a>+DLE+[0002]+[0001]+STX+(R(2),2)+<c> that you posted does not exist in any of the SEND or RECV messages in the enclosed zip file. The closest match is the SEND message: <a>+[10]+[0002]+[0001]+[02]+(R(2),2)+<c> This is a Modbus protocol message that means the following: <a> = Whatever is specified in the Address <a> column (see below) Currently the address field is (R(1),1) which is the 1st word of the read table in the PLC which holds the inverter address one byte long [10] = Hex Constant of &H10 which is the Modbus Command Code for WRITE [0002] = Hex Constant of &H0002 which is the Modbus Register Number in the Inverter [0001] = Hex Constant of &H0001 which is how many Modbus registers to WRITE [02] = Hex Constant of &H02 which is the number of BYTES to WRITE (usually twice the number of Modbus REGISTERS to WRITE) (R(2),2) = which is the 2nd word of the read table in the PLC which holds the actual data to be written to the specified Modbus Register(s) two bytes long <c> = which is a calculation specified in the Check Code <c> column (see below) which is currently is set to CRC16 which is the Check code for Modbus protocol

[Derickvdw 0]

Thanx Jay. I was almost on the right track. It is just the DLE and the STX that had me confused.