ProSoft Technology PTQ-104C - Manual (Page 90)

Hot Standby Support 49TPTQ-104C ♦ 48TQuantum Platform
12TUser Manual 47TIEC 60870-5-104 Client
%SW60.3: Setting this bit = 0 will force the Standby PLC offline if a logic
mismatch is detected. Logic mismatch is defined as either the MID, LID or CID
being different on Primary and Standby sides. Setting this bit = 1 will allow the
Standby PLC to continue to operate normally even if the MID is different on the
Primary and Standby.
%SW60.4: Setting this bit = 1 allows the executive to upgrade on the Standby
without having to stop the application. This means the Hot Standby system is
allowed to operate with different versions of the OS running on the Primary and
Standby. This option is provided to allow upgrades to be done without shutting
down the process. Clearly, the Standby PLC must be stopped to do the executive
upgrade, but it will be able to operate as a valid Standby when started again.
%SW60.5: Setting this bit = 1 commands the standby station to initiate an
application transfer. That function is not required in UNITY V1.
%SW60.8: If this bit is set = 1 the Modbus address on port 1 will be swapped
when a switchover occurs. Swapping means to change address by ± 128 to keep
the address in the range of 1 to 247. The purpose of this is to allow the P-unit of
an HMI to always use the same address to connect to the Primary or
Standby/Offline PLC.
PLC HSBY Status Register
The Status Register provides user information relative to the state of the two
PLCs in the Hot Standby system. The Status Register is %SW61.
Both the Primary and Standby/Offline PLCs have their own copies of the Status
register. The Status register is not transferred from Primary to Standby each
scan. Each PLC must maintain its local Status Register based on the regular
communication between the two PLCs.
The following illustration identifies the operating options provided by the
Command Register.
%SW61 Hot Standby Status Register
The following gives additional detail on the various parts of the Status Register.
Page 90 of 136 ProSoft Technology, Inc.
March 4, 2013