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be identified on the LAN, and sends/receives
them. Messages are classified and handled as
follows according to the operation sequence of
VISCA communication.
VISCA command
This is a command from the controller to the
peripheral device.
When the peripheral device receives this
command, ACK is returned. After completing
command processing, a completion notice is
returned. This command uses the socket of
VISCA. The order of completion notices may be
changed if the multiple commands are sent to
the same peripheral device.
VISCA inquiry
This is an inquiry from the controller to the
peripheral device.
When the peripheral device receives this type of
command, the reply for the inquiry is returned.
This command does not use the socket of VISCA.
The order of the replies is not changed if a
multiple commands are sent simultaneously.
VISCA reply
This is an ACK, completion notice, reply, or error
reply from the peripheral device to the controller.
VISCA device setting command
This is the device setting command from the
controller to the peripheral device as follows.
When the peripheral device receives this type of
command, the command is activated.
• IF_Clear
Clears the command buffer in the unit. When
cleared, the operation currently being
executed is not guaranteed. Sends the reply
message to the controller after clearing,
without using VISCA socket.
• CAM_VersionInq
Returns information on the VISCA interface
within the unit. Sends the reply message to the
controller, without using a VISCA socket.
Socket
When command messages are sent to the unit, it
is normal to send the next command message
after receiving the completion message or error
message. However, to deal with advanced uses,
the unit has two sets of buffers (memories) for
commands, so that up to two commands
including the commands currently being
executed can be received. These buffers are
called sockets. (There is a wait longer than a 1V
cycle between commands.) However, depending
on the command, it may be necessary to wait
until the first command is completed due to
system reasons. When the unit receives
commands, it notifies which command buffer
was used using the socket number of ACK
message. As the completion message or error
message also has a socket number, it indicates
which command has ended. Even when two
command buffers are being used, the unit
management command and inquiry messages
can be executed.
The ACK message is not returned for these
commands and inquiries, and only the
completion message of socket number 0 is
returned.
Format
These are the specifications of the message
header (8 bytes) and payload (1 to 16 bytes).
Message (9 to 24 bytes)
Message
header
Payload type Payload length
Message structure
Note
The actual LAN out method is big-endian, LSB
first.
4
Payload (1 to 16 bytes)
Sequence number
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