Varian TV 301 Manual De Instrucciones página 39

− <STX> (Start of transmission) = 0x02
− <ADDR> (Unit address) = 0x80 (for RS 232)
<ADDR> (Unit address) = 0x80 + device num-
ber (0 to 31) (for RS 485)
− <WIN> (Window) = a string of 3 numeric char-
acter indicating the window number (from '000'
to '999'); for the meaning of each window see
the relevant paragraph.
− <COM> (Command) = 0x30 to read the window,
0x31 to write into the window
− <DATA> = an alphanumeric ASCII string with
the data to be written into the window. In case
of a reading command this field is not present.
The field length is variable according to the
data type as per the following table:
DATA TYPE FIELD
LENGTH
Logic (L) 1
Numeric (N) 6
Alphanumeric (A) 10
− <ETX> (End of transmission) = 0x03
− <CRC> = XOR of all characters subsequent to
<STX> and including the <ETX> terminator.
The value is hexadecimal coded and indicated
by two ASCII character.
The addressed SLAVE will respond with an AN-
SWER whose structure depends from the MESSAGE
type.
When the MESSAGE is a reading command, the
SLAVE will respond transmitting a string with the
same structure of the MESSAGE.
NOTE
Using the RS 485 interface, the message structure
remains identical to the one used for the RS 232
interface, the only difference being that the value
assigned to the ADDRESS <ADDR>
Examples:
Command: START
Source: PC
Destination: Controller
02 80 30 30 30
STX ADDR WINDOW
All manuals and user guides at all-guides.com
VALID
CHARACTERS
'0' = OFF
'1' = ON
'-', '.', '0' . . . '9' right
justified with '0'
from blank to '_' (ASCII)
31 31 03 42 33
WR ON ETX CRC
34
TECHNICAL INFORMATION
Source: Controller
Destination: PC
02 80 06 03 38
STX ADDR ACK ETX CRC
Command: STOP
Source: PC
Destination: Controller
02 80 30 30 30
STX ADDR WINDOW
Source: Controller
Destination: PC
02 80 06 03 38
STX ADDR ACK ETX CRC
Command: SOFT-START (ON)
Source: PC
Destination: Controller
02 80 31 30 30
STX ADDR WINDOW
Source: Controller
Destination: PC
02 80 06 03 38
STX ADDR ACK ETX CRC
Command: SOFT-START (OFF)
Source: PC
Destination: Controller
02 80 31 30 30
STX ADDR WINDOW
Source: Controller
Destination: PC
02 80 06 03 38
STX ADDR ACK ETX CRC
35
31 30 03 42 32
WR OFF ETX CRC
35
31 31 03 42 32
WR ON ETX CRC
35
31 30 03 42 33
WR OFF ETX CRC
35
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