Serial Communication Port; Rs 232 Communication Descriptions; Transmission Channel Characteristics; Message Structure - Varian Turbo-V 300 SQ 275 Instruction Manual

Serial Communication Port

Communication serial port connections and mini- mum
connection configuration are shown in the following
figures. The communication port mating connector is
supplied with the RS 232 PCB (AMP/Cannon or
equivalent 9-pin "D" type male connector). The external
cable (not supplied) between the host computer and the
controller does not require crossed wires so that signals
are connected correctly .
For example, the Transmit data signal from controller
(pin 2) must be connected to the host computer's
Receive data line (pin 2) and vice versa. Consult the
host computer's instruction manual for its serial port
connections
Varian cannot guarantee
regulations for radiated emissions unless all external
wiring is shielded, with the shield being terminated to
the metal shroud on the O-subconnector. The cable
should be secured to the connector with screws.
!
In order to avoid possible conflicts on the Serial Line, it
is advisable to use a 3 wire shielded cable for the TxD,
RxD and GND connections and to leave all the other
pins unconnected.

RS 232 Communication Descriptions

Communication RS 232 serial port connections
NOTE
compliance with
WARNING!

Transmission Channel Characteristics

levels:
baud rate:
character length:
parity:
stop bit:
protocoll:
In this case the value to be assigned to the ADDRESS
field must be 80 hex (for RS 232).

Message Structure

(request and answer have the same format)
The master system (PC) starts every session sending
the following message to the slave units connected:
FCC
<STX> / <ADDR> + <WINDOW> + <COMMAND> +
<DATA> + <ETX> + <CRC>
where:
<STX>=
<ADDR> =
<ADDR> =
<WINDOWS>=
<COMMAND>=
<DATA> =
<ETX>=
<CRC>=
5
TECHNICAL INFORMATION
RS 232/RS 422
9600/4800
programmable by a jumper on the
board
8 bits
none
1 bit
master (PC) / slave (converter)
0x02
0x80 (for RS 232 and
RS 422 only)
0x80 + device number (0...31)
0xFF: brodcasting command
(recognized by all the devices, it
doesn't implicate any answer)
(for RS 485 only)
'000'...' 999' window number
the meaning of the window
depends to the device type
0x30 :window value reading
0x31 :window writing
alphanumeric ASCII string
containing, in the case of writing
operation, the parameter to input
into the window addressed by
the field <WINDOW>This field
may have variable length
according to the data type
contained in the window where
you are working in. In the case of
reading request of a window, the
data field doesn't exist.
0x03
XOR among all the characters
following <STX>=(with exception of
<STX>), including the end
character <ETX> hexadecimally
encoded by two ASCII characters.
87-900-944-01 (C)