Sierra Video Sequoia Family - Manual (Page 25)

SIERRA VIDEO SYSTEMS
19
Theory of
Operation
Control System Overview
A high quality routing switcher system requires that a high performance switching system be
combined with a flexible, reliable and easy-to-use control system. The control system used with
Sequoia routing switchers builds upon the proven capabilities of the time-tested Tahoe control
system. There are well over 10,000 Sierra Video Systems Tahoe Series routing switchers in
service throughout the world today. The Sequoia control system is completely compatible with all
Tahoe Series products. Therefore all control panels that work on a Tahoe Series routing switcher
will work with a Sequoia Series router.
The easy to use SVS serial protocol is used for control of the router by external devices. In
applications where automation or third party control systems are used, this protocol provides
complete control and configuration remotely. The control system protocol is compatible with all
Tahoe and Shasta family products and is supported by multiple control and automation
companies (see Chapter on Communication Protocol).
A wide variety of control panels are available, operating on the standard Sierra Video Systems
RS-485 control panel network using a simple twisted pair of wires. Control panels can be located
up to 5,000 feet (1,500 m) away from the frame. Each system has a capacity of up to 100 panels.
Non-volatile RAM
The control processor board contains non-volatile memories, which are used to store the
crosspoint matrix state, salvo presets, input/output/level names, control panel configuration, and
other non-volatile information. Any information stored in the non-volatile RAM remains valid when
the switcher is powered down. This allows the switcher to return the router to its previous state
when power is restored. When power is applied to the router the non-volatile RAM data is
checked for validity and then all crosspoints are set to the values they last had when the
processor was previously running.
Although it is not recommended, it is possible to force re---initialization of the non-volatile RAM. If
re-initialization is forced, there is the possibility that all existing customization and configuration
data will be lost, and it can be a lengthy procedure to restore the data. However, in some cases it
Chapter 3