Edwards STP-iXA4507 Series - Protocol and Transmission Standards

STP-iXA4507 series Turbomolecular Pump
MT-91E-001-0
Page 69
SERIAL COMMUNICATION PROTOCOL
5
5.3 Protocol specifications
5.3.1 General description
In the STP serial communication protocol, a SIM(s) receives communication commands transmitted
from a PC (Figure 39-1), and sends a response following the communication commands (Figure 39-
2). The communication commands from a PC transmit a text message (ASCII text) assigned to each
function. The communication commands include the control commands (the STP pump operation
commands) and the query commands (read-out of the STP pump operation modes).
1. Communication command
2. Response
Figure 39 - PC to SIM communication
Table 20 shows ASCII characters used in the transmission procedures, error procedures, and
handshake in the application layer.
ASCII
character
HEX
code
Function
Transmission layer
Stx
02
Transmission block start character
Etx
03
Transmission frame end character
Etb
17
Transmission block end character
Ack
06
Acknowledgment response
Nak
15
Non-acknowledgment response
@
40
Network frame ID character
Application layer
#
23
Acknowledgment response
!
21
Non-acknowledgment response
Table 20 - Transmission control characters
1
2