Edwards STP-iX457 Series - Page 94

STP-iX457/iXU457 Series Turbomolecular Pump
MT-86E-001-F
Page 84
5
SERIAL COMMUNICATION PROTOCOL
Examples: Network frame ID character and number in the multi-point connection
ASCII @ 0 1 Network frame No "1"
HEX 40 30 31
ASCII @ 6 4 Network frame No "100"
HEX 40 36 34
ASCII @ 7 F Network frame No "127"
HEX 40 37 46
The transmission frame has a single block or multiple transmission blocks. Each transmission block
consists of a network frame ID character, a network frame number, a start control character, data
block number (3 digits), a message (up to 255 characters), an end control character and a checksum
(LRC). The following shows the transmission frame when the message transmission character string
is C
n
.
Transmission frame when a message is below 255 characters (n<=255):
1 2 3 4 5 6 7 8 8+n 8+n+1 8+n+2
ASCII
@ F
1
F
2
Stx 0 0 1 C
1
C
n
Etx LRC
"@" is used as a network frame ID character.
"Stx" and "Etx" are used as a start and an end character of the transmission frame, respectively.
Transmission frame when a message exceeds 255 characters (n = 255, m<=255, k = the number of
transmission blocks)
First 1 2 3 4 5 6 7 8 8+n 8+n+1 8+n+2
Block ASCII @ F
1
F
2
Stx 0 0 1 C1
1
C1
n
Etb LRC
Second 1 2 3 4 5 6 7 8 8+n 8+n+1 8+n+2
Block ASCII @ F
1
F
2
Stx 0 0 2 C2
1
C2
n
Etb LRC
Final 1 2 3 4 5 6 7 8 8+m 8+m+1 8+m+2
Block ASCII @ F
1
F
2
Stx k Ck
1
Ck
m
Etx LRC
"@" is used as a network frame ID character.
"Stx" is a start character of each transmission block, and "Etb" is an end character of the transmission
block of a message of 255 characters.
"Etx" is used as an end character of the final transmission block (end character of the transmission
frame).