Sierra Video Sequoia Family - Manual (Page 31)

THEORY OF OPERATION
25
Diagnostics
When the switcher is powered up or resets for any reason, it performs a series of self-tests,
signaling progress using the LEDS as follows:
All LEDS are flashed quickly for about one second, immediately after startup (after initializing the
processor registers). This indicates that the processor is up and running and that the LEDS work.
The LEDs with then go through a diagnostics sequence which lasts about ½ second, then turns
the LEDs off. Then the LEDS will begin normal operation as described above.
Synchronization with House reference
There are three sets of looping reference BNC connectors. If there is nothing connected to any of
these BNC, the “not locked” LED will blink at a rate of 3 times/second and the router will operate
completely normally. If it is desirable for the router to switch during the video vertical interval,
then the control system should be locked to an external signal. The external reference can be
any valid NTSC/PAL composite video signal (although black is recommended). Any of the
reference loop through BNCs can be used, however only connect one reference signal to the
router. When the router is locked to an external reference, the “not locked” LED will become a
software idle counter and blink about once every 8 seconds.
When the router control system is locked to a reference crosspoints will be switched at a field
boundary of the video. In addition, deterministic control is possible using the Host serial port.
The delay between receiving a command and performing a crosspoint switch can be set to
practically any number of frames so that the control system can be tailored to the requirements of
any automation or external control system.
Five Port Controller System
The Sequoia Series control system has a total of 5 serial control ports.
One of these ports is dedicated to the RS485 based control panel system. A network of up to 100
Sierra Video Systems control panels can be linked via shielded twisted-pair audio or data cable.
A variety of control panel types are available, including a push-button keypad or "shot" panel.
The Control Panel ports are marked “CTL PNL (RS-485)”.
Multi-Drop Ports 1, 2, 3 and 4 are used to control the crosspoint hardware. The Sequoia control
system uses hi speed serial communications and these ports are used to connect all of the
frames within a single system to the CPU. It is not important which Multi-Drop port is used as
long as there is a connection between each and every frame in the system and one of the four
Multi-Drop ports on the CPU.
Port 1 and Port 2 can be used as either RS232 or RS422 host control ports using a variety of
popular data rates. Either port can be used as a simple terminal control port or as a Host control
port using the Sierra Video Systems serial control protocol.
Port 3 can be used as either RS485 or RS422 host control ports using a variety of popular data
rates. This port can be used as a simple terminal control port, a Host control port, or as an extra
control panel network allowing more that 100 control panels.
The ports can be connector to a wide variety of external devices. The most common is a PC,
which is why we also supply the Sierra Video Systems Windows 95/98/NT program, known as
GRIP (Graphical Router Interface Program) with each router. When software control systems
grow and needs increase, such as tielining and network capability, Sierra offers Intellipath
software to fill these needs.