Primary and
Standby System
Unit Control
Register
(%SW60)
Schneider Electric recommends you become familiar with the Hot Standby control
register.
Locate the "Invalidate keypad" bit, which is the LSB. The Invalidate Keypad bit (bit
15) dictates the state of the "A-Controller", and bit 14 dictates the state of the "BController".
An additional screen menu, named Diag, appears on the controller’s LCD display
screen. These menus describe the state of t5he controller.
The Diag field indicates whether the current CPU is in Run mode (plug&run) or not.
If the current controller is not in RUN mode, the keypad displays the reason for the
offline state: keypad and / or control register.
Additional
Information
about Using the
Control Register
If the keypad LED displays a "Mode" field in the "Hot Standby" screen, that gives the
intention emitted by the user through the keypad, concerning the Run/Offline (i.e.
coupled/uncoupled) state of the current CPU in regard with the Hot Standby system.
In turn the Hot Standby Control Register (%SW60), through bits 15 and 14, permits
an external host system to set the mode to either a Run or Offline state for the
current CPU and/or the alternate CPU. These bit positions are accessible by the
application program and / or an external system such as a SCADA system or a
programming panel.
The intentions emitted by the Control Register bits always play their part in the final
decision, concerning the Run/Offline state of the CPU units.
The intentions emitted by the keypad Mode selections (Run versus Offline) play their
respective part in the final decision, concerning the Run/Offline state of the CPU
units, provided the Keypad Disable bit position (LSB) in the HSBY Control
Register.1. is in the False state ('0'). In these conditions, for a given CPU, either the
Control Register bit position governing its Run/Offline CPUs State, and the Mode
field value of the CPU's keypad, should ask for a 'Run', in order to get an effective
'Run' state. 2.
2.When keypad becomes validated again, the keypad selections take effect
immediately.1.The Standby's Control Register is updated on each scan cycle with
the contents of the Primary's Control Register 1.
LCD Display Screen
Menu
Description
Diag: off keypad Offline mode selected using the keypad
Diag: off %sw60 Offline mode selected using the control register and possibly the
keypad
Diag: plug&run Online mode selected using either the keypad or the control
register
Shipping Port: Xiamen, China
