VL-422 Communication Protocol (DeputyDome)
1
Message Format
Data is transmitted at 9600 baud, 1 start bit, 1 stop bit, 8 data bits (lsb first), no parity. The general format for messages sent to the DeputyDome and for
inquiry response messages sent by the DeputyDome is shown below:
BYTE
DATA
DESCRIPTION
1
F8H
Sync character
2
Address in hex
Camera address (01H – DFH)
3 to N-1
Command Data
All command characters are 8-bit characters; most are ASCII characters.
N
Terminator and
Checksum
80H - 8FH Most significant bit is always 1. Least significant (LS) nibble is XOR of all previ-
ous bytes (LS nibble only) except for the leading character F8H.
The acknowledge message sent from the DeputyDome shall consist of a single hexadecimal 06 character. The negative acknowledge message shall
consist of a single hexadecimal 15 character. Characters enclosed in quotes represent ASCII characters and numbers followed by an “H” are hexadecimal
numbers.
2
Message Sequence
Each message transaction is initiated by the controller. The DeputyDome shall respond to each successfully received message with an ACK message no
sooner than 1ms. and no later than 20ms. after the last byte of the message has been received. If the message is not understood by the DeputyDome, a
NACK message will be sent.
If an inquiry message is successfully received from the host, the DeputyDome shall respond with the ACK message as previously described and the inquiry
response shall then be transmitted no sooner than 1ms. and no later than 100ms. after the transmission of the ACK.
3
Command Messages
These commands control the basic motion of the pan/tilt platform and the lens movement of the camera system. Byte number 1 is the start
of message F8, byte number 2 is the device address (default = 01), and byte number five is the message terminator byte.
3.1
Motion Command Messages
FUNCTION
Byte #3
Byte #4
DESCRIPTION
PAN LEFT
“P”
“L”
Move at default speed.
PAN RIGHT
“P”
“R”
Move at default speed.
PAN STOP
“P”
“S”
TILT UP
“T”
“U”
Move at default speed.
TILT DOWN
“T”
“D”
Move at default speed.
TILT STOP
“T”
“S”
ZOOM IN
“Z”
“I”
Zoom In (Telephoto)
ZOOM OUT
“Z”
“O”
Zoom Out (Wide angle)
ZOOM STOP
“Z”
“S”
FOCUS NEAR
“F”
“N”
FOCUS FAR
“F”
“F”
FOCUS STOP
“F”
“S”
IRIS OPEN
“I”
“O”
IRIS CLOSE
“I”
“C”
IRIS STOP
“I”
“S”
PAN LEFT AT SPEED “x”
“l”
“0” - “?”
Pan left at speed index 0-15. (“l” is lower-case “L”.)
PAN RIGHT AT SPEED “x”
“r”
“0” - “?”
Pan right at speed index 0-15.
TILT UP AT SPEED “x”
“u”
“0” - “?”
Tilt up at speed index 0-15.
TILT DOWN AT SPEED “x”
“d”
“0” – “?”
Tilt down at speed index 0-15.
