GE Industrial Solutions Entellisys Integrator’s Guide - Manual (Page 17)

Modbus ® protocol implementation 17
1.1.6.2 Modbus password operation
The COMMAND password is set up at memory location 0458h. Storing a value of “0” removes
COMMAND password protection. When reading the password setting, the encrypted value (zero
if no password is set) is returned. COMMAND security is required to change the COMMAND
password.
Similarly, the SETTING password is set up at memory location 045Ah. To gain COMMAND level
security access, the COMMAND password must be entered at memory location 045Ch. To gain
SETTING level security access, the SETTING password must be entered at memory location
045Eh. The entered SETTING password must match the current SETTING password setting, or
must be zero, to change settings or download firmware.
COMMAND and SETTING passwords each have a 30-minute timer. Each timer starts when you
enter the particular password, and is restarted whenever you “use” it. For example, writing a
setting restarts the SETTING password timer and writing a command register or forcing a coil
restarts the COMMAND password timer. The value read at memory location 0460h can be used
to confirm whether a COMMAND password is enabled or disabled (0 for Disabled). The value
read at memory location 0461h can be used to confirm whether a SETTING password is
enabled or disabled.
COMMAND or SETTING password security access is restricted to the particular port or particular
TCP/IP connection on which the entry was made. Passwords must be entered when accessing
the relay through other ports or connections, and the passwords must be reentered after
disconnecting and reconnecting on TCP/IP.