User manual

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

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