User manual

PTQ-104S Rev2 ♦ Quantum Platform Hot Standby Support
IEC 60870-5-104 Server for Quantum User Manual
ProSoft Technology, Inc. Page 109 of 195
February 22, 2013
%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.
%SW61.0 to 3: These bits display the state of the local and remote Hot Standby
PLCs.
%SW61.4: This bit is set = 1 whenever a logic mismatch is detected between the
Primary and Standby PLCs. This means that either the MID, CID or LID is
different on the two PLCs. Under this condition, if bit 13 of the Command
Register is set = 0, bit 1 of the Status Register will be set = 1.
%SW61.5: This bit identifies the order reported by the Copro at start time
depends on the range of the MAC addresses.
 If the A/B designation is A, then bit 5 will be set = 0.
 If the A/B designation is B, then bit 5 will be set = 1.