User manual

Hot Standby Support PTQ-104S Rev2 ♦ Quantum Platform
User Manual IEC 60870-5-104 Server for Quantum
Page 108 of 195 ProSoft Technology, Inc.
February 22, 2013
%SW60 Hot Standby Command Register
%SW60.0: This bit, if set to 1, allows the Command Register RUN status of the
PLC to be set through the LCD Keypad.
Warning: If the keypad override is enabled while the Hot Standby system is running, the Primary
PLC will immediately read bits 14 and 15 to determine its own state and the state of the Standby. If
both bits are set to 0, a switchover will occur and the former Primary will go offline. The new
Primary will continue to operate.
%SW60.1: Setting this bit = 1 will put PLC A in RUN mode. Setting the bit = 0 will
put PLC A in OFFLINE mode. This bit takes effect only if bit 16 is set = 1.
%SW60.2: Setting this bit = 1 will put PLC B in RUN mode. Setting the bit = 0 will
put PLC B in OFFLINE mode. This bit takes effect only if bit 16 is set = 1.
%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.