5
Introduction
TallyMan TM1 MK3+ redundancy allows TallyMan control systems to continue to operate when an
unexpected issue occurs, or a system controller needs to be taken offline for maintenance. It operates on
an A->B failover basis: if a failover event occurs then the system will automatically deactivate its Primary
controller and activate the Backup controller so that operations can continue. This type of failover system
offers protection from events such as power failure, network interruptions or system failure and greatly
improves the ability to maintain operations in the occurrence of a failover event.
The TallyMan redundancy system has both automatic and manual failover modes, meaning that an
operator can change the failover mode from auto to manual to perform maintenance tasks with minimal
disruption to operation.
Terminology
The table below lists the terms used in this guide, along with the abbreviations that appear on the
TallyMan Redundancy Panel (TMRP) buttons.
The unit that is expected to be in use during normal operation. Even if it fails over to the Backup
unit, it is still called the Primary.
The unit that is ready to take over from the Primary in the event of a failover. Even if it becomes
Active, it is still called the Backup, since it is assumed that normal service will eventually be
restored, and the Primary will take control again.
The Active TM1 (either Primary or Backup) has functional control over the redundancy system.
The Standby TM1 is working correctly and ready to take over functional operations when
required. Note the ability to take over control is determined by other settings within the system
such as the Failover Mode.
A TM1 that is in the process of becoming Active.
A TM1 that is in the process of Deactivating to enter Standby mode.
A TM1 that is not available to be either Active or in Standby mode.
The Failover mode, changes between Auto and Manual failover operations.
Automatic Failover mode – The system monitors itself to determine if a failover event has
occurred and then implements the failover action.
Manual Failover mode – The user is free to change over the Active unit manually; while in this
mode the system will not failover automatically.
Failover mode is in Auto AND the system is ready to act in the occurrence of a failover event.
This is only available if the Primary is Active.
Failover mode is in Auto AND the system has triggered a Failover action. The Backup TM1 is the
Active unit.
Failover mode is in Auto. However, the system is not able to act in the occurrence of a Failover
event. This could be due to a physical connection issue, network issues or errors in the system.
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