Edwards STP-iXA4507 Series - Page 81

STP-iXA4507 series Turbomolecular Pump
MT-91E-001-0
Page 71
SERIAL COMMUNICATION PROTOCOL
5
Transmission frame when data is transmitted with one block (a message is less than 256
characters):
Designate the control command on a PC first.
<- Less than 256 chr. ->
PC->SIM
Stx
0
0
1
Sp
CHR
C
1
C
n
Etx
LRC
SIM->PC
Ack or Nak
Parameter characters are less than 254 characters (n< 254) when a message is less than 256
characters.
Then the preceding SIM->PC character is "Ack", the instructed control command is executed, and
the SIM returns the following response.
PC->SIM
Ack or Nak
SIM->PC
Stx
0
0
1
# or !
Etx
LRC
The PC transmits "Ack" or "Nak"; then transmits the next command if necessary.
Transmission frame when data is transmitted to two blocks (message is more than 256 characters
and less than 512 characters):
Designate the control command (the 1st block) on a PC first.
PC->SIM
Stx
0
0
1
Sp
CHR
C
1
C
253
Etb
LRC
SIM->PC
Ack or Nak
Next, when the preceding SIM->PC character is "Ack", the PC continues instructing the following
control command (the 2nd block).
PC->SIM
Stx
0
0
2
C
254
C
n
Etx
LRC
SIM->PC
Ack or Nak
The parameter characters are less than 510 characters (n< 510) when a message is less than 512
characters.
Then if the preceding SIM->PC character is "Ack", the instructed control command is executed, and
the SIM returns the following response.
PC->SIM
Ack or Nak
SIM->PC
Stx
0
0
1
# or !
Etx
LRC
The PC transmits "Ack" or "Nak"; then transmits the next command if necessary.