ABB Relion 620 Series Protocol Manual page 40

Section 3
Vendor-specific implementation
34
With the control operations the client must assemble the control structure register
values and write them into the IED.
Execute register
The control step is executed when value "1" is written into this register.
Password register 1
If a password is defined, the first two ASCII characters of the four character password
are written into this register: the first character into the higher byte and the second
character into the lower byte of the register. If no password is defined for the control
structure, this register is not checked by the IED.
For example, having 'ab' as the first two characters of the password, the correct register
value to be written by the master is derived the following way: 'ab' = 0×61 0×62 (hex)
= 01100001 01100010 (bin) = 24930 (Int16).
Password register 2
If a password is defined, the last two ASCII characters of the four character password
are written into this register: the third character into the higher byte and the fourth
character into the lower byte of the register. If no password is defined for the control
structure, this register is not checked by the IED.
For example, having 'cd' as the last two characters of the password, the correct register
value to be written by the master is derived the following way: 'cd' = 0×63 0×64 (hex)
= 01100011 01100100 (bin) = 25444 (Int16).
Value register
Set the register bit corresponding to the output to the proper write value. For pulse type
outputs the value is always "1".
Bitmask register
Set the register bit corresponding to the object to be operated to "1". All other bits must
be set to zero.
Control structure register assembling order
The Modbus client can assemble all the control structure registers and write them in
one multiple registers write function 16 request.
The Modbus client can also write the registers in several separate transactions or even
one by one using registers write function 06. The execute register has to be written last
and no more than 15 seconds may occur between the separate register writes. The
control structure operation will time out after 15 seconds after the last register write.
1MRS757645 B
620 series
Communication Protocol Manual