RSView Supervisory Edition Installation Guide

5 • WORKING WITH DISTRIBUTED APPLICATIONS• • • • •How RSView SE Clients respond to server disruptionsDuring server disruptions, users do not have to restart the RSView SE Client software tocontinue using the system. Once the system has switched to the secondary HMI server, ordata server, RSView SE Clients continue functioning normally.About HMI-server redundancyYou can set up redundant operation for HMI servers to provide minimal disruption ofsystem operation in the event that clients lose service from a server, for example, becauseof network or computer failures.For more information, see “Redundant HMI servers” on page 26-6.5 • PlaceholderThe operational status of HMI serversThere are four possible states for an HMI server:• Active applies to any HMI server. It means that the server is running and able to servedata to clients that connect to it.• Standby applies to the inactive HMI server in a redundant server pair. It means thatthe server is running, and will replace the active server if the active server fails.• Out of service applies to any HMI server. It means that the server has been created,but cannot be contacted.• Unknown applies to the secondary server in a redundant server pair. It means that thesecondary server has not been created yet.You can view the operational status of an HMI server in the General tab in the HMIServer Properties dialog box. You can also use VBA code on the RSView client todetermine the status of HMI servers.File synchronizationWhile the server is active, changes made to files (for example, configuration files, or logfiles) are not automatically synchronized on the secondary server.If synchronization is required, the files must be synchronized manually after the changesare made. You can do this by copying the files using Windows Explorer.For details, see “Synchronizing redundant HMI servers and projects” on page 27-11.Alarm state synchronizationAlarm states are synchronized automatically, between primary and secondary HMIservers in a redundant pair.For alarm states to be synchronized properly, the clocks on the primary and secondaryHMI servers must be kept synchronized to a time server. If the clocks on both computers5-7