User manual
Hot Standby Support PTQ-104S Rev2 ♦ Quantum Platform
User Manual IEC 60870-5-104 Server for Quantum
Page 102 of 195 ProSoft Technology, Inc.
February 22, 2013
7.1 Hot Standby Overview
This section describes the PTQ-104S IEC 60870-5-104 Server module
specifications and startup support for Modicon Quantum Hot Standby system.
A Modicon Quantum Hot Standby with Unity system can be used when downtime
cannot be tolerated. Hot standby systems deliver high availability through
redundancy. A hot standby system consists of two identical configurations.
Modicon Quantum 140 CPU 671 60
Modicon Quantum Power Supply Module
Modicon Quantum RIO Head
ProSoft Technology PTQ-104S module hardware version 2.05 or higher
Modicon Optional Modules (NOE, NOM)
One of the 140 CPU 67160s acts as the Primary controller and the other acts as
the Standby controller. The Primary controller runs the application program and
operates the remote I/O.
Note: The Modicon Quantum RIO Head is required even if the Remote I/O will not be used.
7.1.1 Identical Configurations
Two backplanes are configured with identical hardware and software. One of the
programmable logic controllers (PLCs) functions as the Primary controller and
the other as a Standby controller, and either controller can be put in the Primary
state, but the other must be in the Standby state or offline.
7.1.2 Primary and Standby Controllers
The Primary controller executes the application program, controls the remote I/O,
and updates the Standby controller after every scan (program cycle). If the
Primary controller fails, the Standby controller takes control within one scan. To
determine if the Primary controller failed note controller’s status displayed in the
HE CPU LCD screen and the RIO Head’s status displayed by the RIO Head’s
LEDs.
The Standby controller does not execute the full application program but only the
first section, and the Standby controller does not control the remote I/O but
checks out the availability of the Modicon Quantum Hot Standby with Unity
equipment.
Note: For additional information on Quantum Hot Standby support, refer to the Unity Pro Hot
Standby User Guide.